Manual Pages

arpaname - translate IP addresses to the corresponding ARPA names

Synopsis

arpaname {ipaddress …}

Description

arpaname translates IP addresses (IPv4 and IPv6) to the corresponding IN-ADDR.ARPA or IP6.ARPA names.

ddns-confgen - TSIG key generation tool

Synopsis

ddns-confgen [-a algorithm] [-h] [-k keyname] [-q] [-s name] [-z zone]

Description

ddns-confgen is an utility that generates keys for use in TSIG signing. The resulting keys can be used, for example, to secure dynamic DNS updates to a zone, or for the rndc command channel.

The key name can specified using -k parameter and defaults to ddns-key. The generated key is accompanied by configuration text and instructions that can be used with nsupdate and named when setting up dynamic DNS, including an example update-policy statement. (This usage is similar to the rndc-confgen command for setting up command-channel security.)

Note that named itself can configure a local DDNS key for use with nsupdate -l; it does this when a zone is configured with update-policy local;. ddns-confgen is only needed when a more elaborate configuration is required: for instance, if nsupdate is to be used from a remote system.

Options

-a algorithm: This option specifies the algorithm to use for the TSIG key. Available choices are: hmac-md5, hmac-sha1, hmac-sha224, hmac-sha256, hmac-sha384, and hmac-sha512. The default is hmac-sha256. Options are case-insensitive, and the “hmac-” prefix may be omitted.

-h: This option prints a short summary of options and arguments.

-k keyname: This option specifies the key name of the DDNS authentication key. The default is ddns-key when neither the -s nor -z option is specified; otherwise, the default is ddns-key as a separate label followed by the argument of the option, e.g., ddns-key.example.com. The key name must have the format of a valid domain name, consisting of letters, digits, hyphens, and periods.

-q: This option enables quiet mode, which prints only the key, with no explanatory text or usage examples. This is essentially identical to tsig-keygen.

-s name: This option generates a configuration example to allow dynamic updates of a single hostname. The example named.conf text shows how to set an update policy for the specified name using the “name” nametype. The default key name is ddns-key.name. Note that the “self” nametype cannot be used, since the name to be updated may differ from the key name. This option cannot be used with the -z option.

-z zone: This option generates a configuration example to allow dynamic updates of a zone. The example named.conf text shows how to set an update policy for the specified zone using the “zonesub” nametype, allowing updates to all subdomain names within that zone. This option cannot be used with the -s option.

delv - DNS lookup and validation utility

Synopsis

delv [@server] [ [-4] | [-6] ] [-a anchor-file] [-b address] [-c class] [-d level] [-i] [-m] [-p port#] [-q name] [-t type] [-x addr] [name] [type] [class] [queryopt…]

delv [-h]

delv [-v]

delv [queryopt…] [query…]

Description

delv is a tool for sending DNS queries and validating the results, using the same internal resolver and validator logic as named.

delv sends to a specified name server all queries needed to fetch and validate the requested data; this includes the original requested query, subsequent queries to follow CNAME or DNAME chains, queries for DNSKEY, and DS records to establish a chain of trust for DNSSEC validation. It does not perform iterative resolution, but simulates the behavior of a name server configured for DNSSEC validating and forwarding.

By default, responses are validated using the built-in DNSSEC trust anchor for the root zone (“.”). Records returned by delv are either fully validated or were not signed. If validation fails, an explanation of the failure is included in the output; the validation process can be traced in detail. Because delv does not rely on an external server to carry out validation, it can be used to check the validity of DNS responses in environments where local name servers may not be trustworthy.

Unless it is told to query a specific name server, delv tries each of the servers listed in /etc/resolv.conf. If no usable server addresses are found, delv sends queries to the localhost addresses (127.0.0.1 for IPv4, ::1 for IPv6).

When no command-line arguments or options are given, delv performs an NS query for “.” (the root zone).

Simple Usage

A typical invocation of delv looks like:

delv @server name type

where:

server

is the name or IP address of the name server to query. This can be an IPv4 address in dotted-decimal notation or an IPv6 address in colon-delimited notation. When the supplied server argument is a hostname, delv resolves that name before querying that name server (note, however, that this initial lookup is not validated by DNSSEC).

If no server argument is provided, delv consults /etc/resolv.conf; if an address is found there, it queries the name server at that address. If either of the -4 or -6 options is in use, then only addresses for the corresponding transport are tried. If no usable addresses are found, delv sends queries to the localhost addresses (127.0.0.1 for IPv4, ::1 for IPv6).

name: is the domain name to be looked up.

type: indicates what type of query is required - ANY, A, MX, etc. type can be any valid query type. If no type argument is supplied, delv performs a lookup for an A record.

Options

-a anchor-file

This option specifies a file from which to read an alternate DNSSEC root zone trust anchor.

By default, keys that do not match the root zone name (.) are ignored. If an alternate key name is desired, it can be specified using the +root option.

Note: When reading trust anchors, delv treats trust-anchors, initial-key, and static-key identically. That is, for a managed key, it is the initial key that is trusted; RFC 5011 key management is not supported. delv does not consult the managed-keys database maintained by named. This means that if the default key built in to delv is revoked, delv must be updated to a newer version in order to continue validating.

-b address: This option sets the source IP address of the query to address. This must be a valid address on one of the host’s network interfaces, or 0.0.0.0, or ::. An optional source port may be specified by appending #<port>

-c class: This option sets the query class for the requested data. Currently, only class “IN” is supported in delv and any other value is ignored.

-d level: This option sets the systemwide debug level to level. The allowed range is from 0 to 99. The default is 0 (no debugging). Debugging traces from delv become more verbose as the debug level increases. See the +mtrace, +rtrace, and +vtrace options below for additional debugging details.

-h: This option displays the delv help usage output and exits.

-i: This option sets insecure mode, which disables internal DNSSEC validation. (Note, however, that this does not set the CD bit on upstream queries. If the server being queried is performing DNSSEC validation, then it does not return invalid data; this can cause delv to time out. When it is necessary to examine invalid data to debug a DNSSEC problem, use dig +cd.)

-m: This option enables memory usage debugging.

-p port#: This option specifies a destination port to use for queries, instead of the standard DNS port number 53. This option is used with a name server that has been configured to listen for queries on a non-standard port number.

-q name: This option sets the query name to name. While the query name can be specified without using the -q option, it is sometimes necessary to disambiguate names from types or classes (for example, when looking up the name “ns”, which could be misinterpreted as the type NS, or “ch”, which could be misinterpreted as class CH).

-t type

This option sets the query type to type, which can be any valid query type supported in BIND 9 except for zone transfer types AXFR and IXFR. As with -q, this is useful to distinguish query-name types or classes when they are ambiguous. It is sometimes necessary to disambiguate names from types.

The default query type is “A”, unless the -x option is supplied to indicate a reverse lookup, in which case it is “PTR”.

-v: This option prints the delv version and exits.

-x addr: This option performs a reverse lookup, mapping an address to a name. addr is an IPv4 address in dotted-decimal notation, or a colon-delimited IPv6 address. When -x is used, there is no need to provide the name or type arguments; delv automatically performs a lookup for a name like 11.12.13.10.in-addr.arpa and sets the query type to PTR. IPv6 addresses are looked up using nibble format under the IP6.ARPA domain.

-4: This option forces delv to only use IPv4.

-6: This option forces delv to only use IPv6.

Query Options

delv provides a number of query options which affect the way results are displayed, and in some cases the way lookups are performed.

Each query option is identified by a keyword preceded by a plus sign (+). Some keywords set or reset an option. These may be preceded by the string no to negate the meaning of that keyword. Other keywords assign values to options like the timeout interval. They have the form +keyword=value. The query options are:

+cdflag, +nocdflag: This option controls whether to set the CD (checking disabled) bit in queries sent by delv. This may be useful when troubleshooting DNSSEC problems from behind a validating resolver. A validating resolver blocks invalid responses, making it difficult to retrieve them for analysis. Setting the CD flag on queries causes the resolver to return invalid responses, which delv can then validate internally and report the errors in detail.

+class, +noclass: This option controls whether to display the CLASS when printing a record. The default is to display the CLASS.

+hint=FILE, +nohint: This option specifies a filename from which to load root hints; this will be used to find the root name servers when name server mode (delv +ns) is in use. If the option is not specified, built-in root hints will be used.

+ns, +nons

This option toggles name server mode. When this option is in use, the delv process instantiates a full recursive resolver, and uses that to look up the requested query name and type. Turning on this option also activates +mtrace, +strace and +rtrace, so that every iterative query will be logged, including the full response messages from each authoritatve server. These logged messages will be written to stdout rather than stderr as usual, so that the full trace can be captured more easily.

This is intended to be similar to the behavior of dig +trace, but because it uses the same code as named, it much more accurately replicates the behavior of a recursive name server with a cold cache that is processing a recursive query.

+qmin[=MODE], +noqmin: When used with +ns, this option enables QNAME minimization mode. Valid options of MODE are relaxed and strict. By default, QNAME minimization is disabled. If +qmin is specified but MODE is omitted, then relaxed mode will be used.

+ttl, +nottl: This option controls whether to display the TTL when printing a record. The default is to display the TTL.

+rtrace, +nortrace

This option toggles resolver fetch logging. This reports the name and type of each query sent by delv in the process of carrying out the resolution and validation process, including the original query and all subsequent queries to follow CNAMEs and to establish a chain of trust for DNSSEC validation.

This is equivalent to setting the debug level to 1 in the “resolver” logging category. Setting the systemwide debug level to 1 using the -d option produces the same output, but affects other logging categories as well.

+mtrace, +nomtrace

This option toggles logging of messages received. This produces a detailed dump of the responses received by delv in the process of carrying out the resolution and validation process.

This is equivalent to setting the debug level to 10 for the “packets” module of the “resolver” logging category. Setting the systemwide debug level to 10 using the -d option produces the same output, but affects other logging categories as well.

+strace, +nostrace

This option toggles logging of messages sent. This produces a detailed dump of the queries sent by delv in the process of carrying out the resolution and validation process. Turning on this option also activates +mtrace.

This is equivalent to setting the debug level to 11 for the “packets” module of the “resolver” logging category. Setting the systemwide debug level to 11 using the -d option produces the same output, but affects other logging categories as well.

+vtrace, +novtrace

This option toggles validation logging. This shows the internal process of the validator as it determines whether an answer is validly signed, unsigned, or invalid.

This is equivalent to setting the debug level to 3 for the “validator” module of the “dnssec” logging category. Setting the systemwide debug level to 3 using the -d option produces the same output, but affects other logging categories as well.

+short, +noshort: This option toggles between verbose and terse answers. The default is to print the answer in a verbose form.

+comments, +nocomments: This option toggles the display of comment lines in the output. The default is to print comments.

+rrcomments, +norrcomments: This option toggles the display of per-record comments in the output (for example, human-readable key information about DNSKEY records). The default is to print per-record comments.

+crypto, +nocrypto: This option toggles the display of cryptographic fields in DNSSEC records. The contents of these fields are unnecessary to debug most DNSSEC validation failures and removing them makes it easier to see the common failures. The default is to display the fields. When omitted, they are replaced by the string [omitted] or, in the DNSKEY case, the key ID is displayed as the replacement, e.g. [ key id = value ].

+trust, +notrust: This option controls whether to display the trust level when printing a record. The default is to display the trust level.

+split[=W], +nosplit: This option splits long hex- or base64-formatted fields in resource records into chunks of W characters (where W is rounded up to the nearest multiple of 4). +nosplit or +split=0 causes fields not to be split at all. The default is 56 characters, or 44 characters when multiline mode is active.

+all, +noall: This option sets or clears the display options +comments, +rrcomments, and +trust as a group.

+multiline, +nomultiline: This option prints long records (such as RRSIG, DNSKEY, and SOA records) in a verbose multi-line format with human-readable comments. The default is to print each record on a single line, to facilitate machine parsing of the delv output.

+dnssec, +nodnssec: This option indicates whether to display RRSIG records in the delv output. The default is to do so. Note that (unlike in dig) this does not control whether to request DNSSEC records or to validate them. DNSSEC records are always requested, and validation always occurs unless suppressed by the use of -i or +noroot.

+root[=ROOT], +noroot: This option indicates whether to perform conventional DNSSEC validation, and if so, specifies the name of a trust anchor. The default is to validate using a trust anchor of “.” (the root zone), for which there is a built-in key. If specifying a different trust anchor, then -a must be used to specify a file containing the key.

+tcp, +notcp: This option controls whether to use TCP when sending queries. The default is to use UDP unless a truncated response has been received.

+unknownformat, +nounknownformat: This option prints all RDATA in unknown RR-type presentation format (RFC 3597). The default is to print RDATA for known types in the type’s presentation format.

+yaml, +noyaml: This option prints response data in YAML format.

Files

/etc/resolv.conf

dig - DNS lookup utility

Synopsis

dig [@server] [-b address] [-c class] [-f filename] [-k filename] [-m] [-p port#] [-q name] [-t type] [-v] [-x addr] [-y [hmac:]name:key] [ [-4] | [-6] ] [name] [type] [class] [queryopt…]

dig [-h]

dig [global-queryopt…] [query…]

Description

dig is a flexible tool for interrogating DNS name servers. It performs DNS lookups and displays the answers that are returned from the name server(s) that were queried. Most DNS administrators use dig to troubleshoot DNS problems because of its flexibility, ease of use, and clarity of output. Other lookup tools tend to have less functionality than dig.

Although dig is normally used with command-line arguments, it also has a batch mode of operation for reading lookup requests from a file. A brief summary of its command-line arguments and options is printed when the -h option is given. The BIND 9 implementation of dig allows multiple lookups to be issued from the command line.

Unless it is told to query a specific name server, dig tries each of the servers listed in /etc/resolv.conf. If no usable server addresses are found, dig sends the query to the local host.

When no command-line arguments or options are given, dig performs an NS query for “.” (the root).

It is possible to set per-user defaults for dig via ${HOME}/.digrc. This file is read and any options in it are applied before the command-line arguments. The -r option disables this feature, for scripts that need predictable behavior.

The IN and CH class names overlap with the IN and CH top-level domain names. Either use the -t and -c options to specify the type and class, use the -q to specify the domain name, or use “IN.” and “CH.” when looking up these top-level domains.

Simple Usage

A typical invocation of dig looks like:

dig @server name type

where:

server

is the name or IP address of the name server to query. This can be an IPv4 address in dotted-decimal notation or an IPv6 address in colon-delimited notation. When the supplied server argument is a hostname, dig resolves that name before querying that name server.

If no server argument is provided, dig consults /etc/resolv.conf; if an address is found there, it queries the name server at that address. If either of the -4 or -6 options are in use, then only addresses for the corresponding transport are tried. If no usable addresses are found, dig sends the query to the local host. The reply from the name server that responds is displayed.

name: is the name of the resource record that is to be looked up.

type: indicates what type of query is required - ANY, A, MX, SIG, etc. type can be any valid query type. If no type argument is supplied, dig performs a lookup for an A record.

Options

-4: This option indicates that only IPv4 should be used.

-6: This option indicates that only IPv6 should be used.

-b address[#port]: This option sets the source IP address of the query. The address must be a valid address on one of the host’s network interfaces, or “0.0.0.0” or “::”. An optional port may be specified by appending #port.

-c class: This option sets the query class. The default class is IN; other classes are HS for Hesiod records or CH for Chaosnet records.

-f file: This option sets batch mode, in which dig reads a list of lookup requests to process from the given file. Each line in the file should be organized in the same way it would be presented as a query to dig using the command-line interface.

-h: Print a usage summary.

-k keyfile: This option tells dig to sign queries using TSIG or SIG(0) using a key read from the given file. Key files can be generated using tsig-keygen. When using TSIG authentication with dig, the name server that is queried needs to know the key and algorithm that is being used. In BIND, this is done by providing appropriate key and server statements in named.conf for TSIG and by looking up the KEY record in zone data for SIG(0).

-m: This option enables memory usage debugging.

-p port: This option sends the query to a non-standard port on the server, instead of the default port 53. This option is used to test a name server that has been configured to listen for queries on a non-standard port number.

-q name: This option specifies the domain name to query. This is useful to distinguish the name from other arguments.

-r: This option indicates that options from ${HOME}/.digrc should not be read. This is useful for scripts that need predictable behavior.

-t type

This option indicates the resource record type to query, which can be any valid query type. If it is a resource record type supported in BIND 9, it can be given by the type mnemonic (such as NS or AAAA). The default query type is A, unless the -x option is supplied to indicate a reverse lookup. A zone transfer can be requested by specifying a type of AXFR. When an incremental zone transfer (IXFR) is required, set the type to ixfr=N. The incremental zone transfer contains all changes made to the zone since the serial number in the zone’s SOA record was N.

All resource record types can be expressed as TYPEnn, where nn is the number of the type. If the resource record type is not supported in BIND 9, the result is displayed as described in RFC 3597.

-u: This option indicates that print query times should be provided in microseconds instead of milliseconds.

-v: This option prints the version number and exits.

-x addr: This option sets simplified reverse lookups, for mapping addresses to names. The addr is an IPv4 address in dotted-decimal notation, or a colon-delimited IPv6 address. When the -x option is used, there is no need to provide the name, class, and type arguments. dig automatically performs a lookup for a name like 94.2.0.192.in-addr.arpa and sets the query type and class to PTR and IN respectively. IPv6 addresses are looked up using nibble format under the IP6.ARPA domain.

-y [hmac:]keyname:secret: This option signs queries using TSIG with the given authentication key. keyname is the name of the key, and secret is the base64-encoded shared secret. hmac is the name of the key algorithm; valid choices are hmac-md5, hmac-sha1, hmac-sha224, hmac-sha256, hmac-sha384, or hmac-sha512. If hmac is not specified, the default is hmac-md5; if MD5 was disabled, the default is hmac-sha256.

Note

Only the -k option should be used, rather than the -y option, because with -y the shared secret is supplied as a command-line argument in clear text. This may be visible in the output from ps1 or in a history file maintained by the user’s shell.

Query Options

dig provides a number of query options which affect the way in which lookups are made and the results displayed. Some of these set or reset flag bits in the query header, some determine which sections of the answer get printed, and others determine the timeout and retry strategies.

Each query option is identified by a keyword preceded by a plus sign (+). Some keywords set or reset an option; these may be preceded by the string no to negate the meaning of that keyword. Other keywords assign values to options, like the timeout interval. They have the form +keyword=value. Keywords may be abbreviated, provided the abbreviation is unambiguous; for example, +cd is equivalent to +cdflag. The query options are:

+aaflag, +noaaflag: This option is a synonym for +aaonly, +noaaonly.

+aaonly, +noaaonly: This option sets the aa flag in the query.

+additional, +noadditional: This option displays [or does not display] the additional section of a reply. The default is to display it.

+adflag, +noadflag: This option sets [or does not set] the AD (authentic data) bit in the query. This requests the server to return whether all of the answer and authority sections have been validated as secure, according to the security policy of the server. AD=1 indicates that all records have been validated as secure and the answer is not from a OPT-OUT range. AD=0 indicates that some part of the answer was insecure or not validated. This bit is set by default.

+all, +noall: This option sets or clears all display flags.

+answer, +noanswer: This option displays [or does not display] the answer section of a reply. The default is to display it.

+authority, +noauthority: This option displays [or does not display] the authority section of a reply. The default is to display it.

+badcookie, +nobadcookie: This option retries the lookup with a new server cookie if a BADCOOKIE response is received.

+besteffort, +nobesteffort: This option attempts to display the contents of messages which are malformed. The default is to not display malformed answers.

+bufsize[=B]: This option sets the UDP message buffer size advertised using EDNS0 to B bytes. The maximum and minimum sizes of this buffer are 65535 and 0, respectively. +bufsize restores the default buffer size.

+cd, +cdflag, +nocdflag: This option sets [or does not set] the CD (checking disabled) bit in the query. This requests the server to not perform DNSSEC validation of responses.

+class, +noclass: This option displays [or does not display] the CLASS when printing the record.

+cmd, +nocmd: This option toggles the printing of the initial comment in the output, identifying the version of dig and the query options that have been applied. This option always has a global effect; it cannot be set globally and then overridden on a per-lookup basis. The default is to print this comment.

+comments, +nocomments

This option toggles the display of some comment lines in the output, with information about the packet header and OPT pseudosection, and the names of the response section. The default is to print these comments.

Other types of comments in the output are not affected by this option, but can be controlled using other command-line switches. These include +cmd, +question, +stats, and +rrcomments.

+cookie=####, +nocookie

This option sends [or does not send] a COOKIE EDNS option, with an optional value. Replaying a COOKIE from a previous response allows the server to identify a previous client. The default is +cookie.

+cookie is also set when +trace is set to better emulate the default queries from a nameserver.

+crypto, +nocrypto: This option toggles the display of cryptographic fields in DNSSEC records. The contents of these fields are unnecessary for debugging most DNSSEC validation failures and removing them makes it easier to see the common failures. The default is to display the fields. When omitted, they are replaced by the string [omitted] or, in the DNSKEY case, the key ID is displayed as the replacement, e.g. [ key id = value ].

+defname, +nodefname: This option, which is deprecated, is treated as a synonym for +search, +nosearch.

+dns64prefix, +nodns64prefix: Lookup IPV4ONLY.ARPA AAAA and print any DNS64 prefixes found.

+dnssec, +do, +nodnssec, +nodo: This option requests that DNSSEC records be sent by setting the DNSSEC OK (DO) bit in the OPT record in the additional section of the query.

+domain=somename: This option sets the search list to contain the single domain somename, as if specified in a domain directive in /etc/resolv.conf, and enables search list processing as if the +search option were given.

+edns[=#], +noedns: This option specifies the EDNS version to query with. Valid values are 0 to 255. Setting the EDNS version causes an EDNS query to be sent. +noedns clears the remembered EDNS version. EDNS is set to 0 by default.

+ednsflags[=#], +noednsflags: This option sets the must-be-zero EDNS flags bits (Z bits) to the specified value. Decimal, hex, and octal encodings are accepted. Setting a named flag (e.g., DO) is silently ignored. By default, no Z bits are set.

+ednsnegotiation, +noednsnegotiation: This option enables/disables EDNS version negotiation. By default, EDNS version negotiation is enabled.

+ednsopt[=code[:value]], +noednsopt: This option specifies the EDNS option with code point code and an optional payload of value as a hexadecimal string. code can be either an EDNS option name (for example, NSID or ECS) or an arbitrary numeric value. +noednsopt clears the EDNS options to be sent.

+expire, +noexpire: This option sends an EDNS Expire option.

+fail, +nofail: This option indicates that named should try [or not try] the next server if a SERVFAIL is received. The default is to not try the next server, which is the reverse of normal stub resolver behavior.

+fuzztime[=value], +nofuzztime: This option allows the signing time to be specified when generating signed messages. If a value is specified it is the seconds since 00:00:00 January 1, 1970 UTC ignoring leap seconds. If no value is specified 1646972129 (Fri 11 Mar 2022 04:15:29 UTC) is used. The default is +nofuzztime and the current time is used.

+header-only, +noheader-only: This option sends a query with a DNS header without a question section. The default is to add a question section. The query type and query name are ignored when this is set.

+https[=value], +nohttps

This option indicates whether to use DNS over HTTPS (DoH) when querying name servers. When this option is in use, the port number defaults to 443. The HTTP POST request mode is used when sending the query.

If value is specified, it will be used as the HTTP endpoint in the query URI; the default is /dns-query. So, for example, dig @example.com +https will use the URI https://example.com/dns-query.

+https-get[=value], +nohttps-get: Similar to +https, except that the HTTP GET request mode is used when sending the query.

+https-post[=value], +nohttps-post: Same as +https.

+http-plain[=value], +nohttp-plain: Similar to +https, except that HTTP queries will be sent over a non-encrypted channel. When this option is in use, the port number defaults to 80 and the HTTP request mode is POST.

+http-plain-get[=value], +nohttp-plain-get: Similar to +http-plain, except that the HTTP request mode is GET.

+http-plain-post[=value], +nohttp-plain-post: Same as +http-plain.

+identify, +noidentify: This option shows [or does not show] the IP address and port number that supplied the answer, when the +short option is enabled. If short form answers are requested, the default is not to show the source address and port number of the server that provided the answer.

+idn, +noidn

Enable or disable IDN processing. By default IDN is enabled for input query names, and for display when the output is a terminal.

You can also turn off dig’s IDN processing by setting the IDN_DISABLE environment variable.

+ignore, +noignore: This option ignores [or does not ignore] truncation in UDP responses instead of retrying with TCP. By default, TCP retries are performed.

+keepalive, +nokeepalive: This option sends [or does not send] an EDNS Keepalive option.

+keepopen, +nokeepopen: This option keeps [or does not keep] the TCP socket open between queries, and reuses it rather than creating a new TCP socket for each lookup. The default is +nokeepopen.

+multiline, +nomultiline: This option prints [or does not print] records, like the SOA records, in a verbose multi-line format with human-readable comments. The default is to print each record on a single line to facilitate machine parsing of the dig output.

+ndots=D: This option sets the number of dots (D) that must appear in name for it to be considered absolute. The default value is that defined using the ndots statement in /etc/resolv.conf, or 1 if no ndots statement is present. Names with fewer dots are interpreted as relative names, and are searched for in the domains listed in the search or domain directive in /etc/resolv.conf if +search is set.

+nsid, +nonsid: When enabled, this option includes an EDNS name server ID request when sending a query.

+nssearch, +nonssearch: When this option is set, dig attempts to find the authoritative name servers for the zone containing the name being looked up, and display the SOA record that each name server has for the zone. Addresses of servers that did not respond are also printed.

+onesoa, +noonesoa: When enabled, this option prints only one (starting) SOA record when performing an AXFR. The default is to print both the starting and ending SOA records.

+opcode=value, +noopcode: When enabled, this option sets (restores) the DNS message opcode to the specified value. The default value is QUERY (0).

+padding=value: This option pads the size of the query packet using the EDNS Padding option to blocks of value bytes. For example, +padding=32 causes a 48-byte query to be padded to 64 bytes. The default block size is 0, which disables padding; the maximum is 512. Values are ordinarily expected to be powers of two, such as 128; however, this is not mandatory. Responses to padded queries may also be padded, but only if the query uses TCP or DNS COOKIE.

+proxy[=src_addr[#src_port]-dst_addr[#dst_port]], +noproxy

When this option is set, dig adds PROXYv2 headers to the queries. When source and destination addresses are specified, the headers contain them and use the PROXY command. It means for the remote peer that the queries were sent on behalf of another node and that the PROXYv2 header reflects the original connection endpoints. The default source port is 0 and destination port is 53.

For encrypted DNS transports, to prevent accidental information leakage, encryption is applied to the PROXYv2 headers: the headers are sent right after the handshake process has been completed.

For plain DNS transports, no encryption is applied to the PROXYv2 headers.

If the addressees are omitted, PROXYv2 headers, that use the LOCAL command set, are added instead. For the remote peer, that means that the queries were sent on purpose without being relayed, so the real connection endpoint addresses must be used.

+proxy-plain[=src_addr[#src_port]-dst_addr[#dst_port], +noproxy-plain

The same as +[no]proxy, but instructs dig to send PROXYv2 headers ahead of any encryption, before any handshake messages are sent. That makes dig behave exactly how it is described in the PROXY protocol specification, but not all software expects such behaviour.

Please consult the software documentation to find out if you need this option. (for example, dnsdist expects encrypted PROXYv2 headers sent over TLS when encryption is used, while HAProxy and many other software packages expect plain ones).

For plain DNS transports the option is effectively an alias for the +[no]proxy described above.

+qid=value: This option specifies the query ID to use when sending queries.

+qr, +noqr: This option toggles the display of the query message as it is sent. By default, the query is not printed.

+question, +noquestion: This option toggles the display of the question section of a query when an answer is returned. The default is to print the question section as a comment.

+raflag, +noraflag: This option sets [or does not set] the RA (Recursion Available) bit in the query. The default is +noraflag. This bit is ignored by the server for QUERY.

+rdflag, +nordflag: This option is a synonym for +recurse, +norecurse.

+recurse, +norecurse: This option toggles the setting of the RD (recursion desired) bit in the query. This bit is set by default, which means dig normally sends recursive queries. Recursion is automatically disabled when the +nssearch or +trace query option is used.

+retry=T: This option sets the number of times to retry UDP and TCP queries to server to T instead of the default, 2. Unlike +tries, this does not include the initial query.

+rrcomments, +norrcomments: This option toggles the display of per-record comments in the output (for example, human-readable key information about DNSKEY records). The default is not to print record comments unless multiline mode is active.

+search, +nosearch

This option uses [or does not use] the search list defined by the searchlist or domain directive in resolv.conf, if any. The search list is not used by default.

ndots from resolv.conf (default 1), which may be overridden by +ndots, determines whether the name is treated as relative and hence whether a search is eventually performed.

+short, +noshort: This option toggles whether a terse answer is provided. The default is to print the answer in a verbose form. This option always has a global effect; it cannot be set globally and then overridden on a per-lookup basis.

+showbadcookie, +noshowbadcookie: This option toggles whether to show the message containing the BADCOOKIE rcode before retrying the request or not. The default is to not show the messages.

+showsearch, +noshowsearch: This option performs [or does not perform] a search showing intermediate results.

+split=W: This option splits long hex- or base64-formatted fields in resource records into chunks of W characters (where W is rounded up to the nearest multiple of 4). +nosplit or +split=0 causes fields not to be split at all. The default is 56 characters, or 44 characters when multiline mode is active.

+stats, +nostats: This option toggles the printing of statistics: when the query was made, the size of the reply, etc. The default behavior is to print the query statistics as a comment after each lookup.

+subnet=addr[/prefix-length], +nosubnet

This option sends [or does not send] an EDNS CLIENT-SUBNET option with the specified IP address or network prefix.

dig +subnet=0.0.0.0/0, or simply dig +subnet=0 for short, sends an EDNS CLIENT-SUBNET option with an empty address and a source prefix-length of zero, which signals a resolver that the client’s address information must not be used when resolving this query.

+tcflag, +notcflag: This option sets [or does not set] the TC (TrunCation) bit in the query. The default is +notcflag. This bit is ignored by the server for QUERY.

+tcp, +notcp: This option indicates whether to use TCP when querying name servers. The default behavior is to use UDP unless a type any or ixfr=N query is requested, in which case the default is TCP. AXFR queries always use TCP. To prevent retry over TCP when TC=1 is returned from a UDP query, use +ignore.

+timeout=T: This option sets the timeout for a query to T seconds. The default timeout is 5 seconds. An attempt to set T to less than 1 is silently set to 1.

+tls, +notls: This option indicates whether to use DNS over TLS (DoT) when querying name servers. When this option is in use, the port number defaults to 853.

+tls-ca[=file-name], +notls-ca: This option enables remote server TLS certificate validation for DNS transports, relying on TLS. Certificate authorities certificates are loaded from the specified PEM file (file-name). If the file is not specified, the default certificates from the global certificates store are used.

+tls-certfile=file-name, +tls-keyfile=file-name, +notls-certfile, +notls-keyfile: These options set the state of certificate-based client authentication for DNS transports, relying on TLS. Both certificate chain file and private key file are expected to be in PEM format. Both options must be specified at the same time.

+tls-hostname=hostname, +notls-hostname: This option makes dig use the provided hostname during remote server TLS certificate verification. Otherwise, the DNS server name is used. This option has no effect if +tls-ca is not specified.

+trace, +notrace

This option toggles tracing of the delegation path from the root name servers for the name being looked up. Tracing is disabled by default. When tracing is enabled, dig makes iterative queries to resolve the name being looked up. It follows referrals from the root servers, showing the answer from each server that was used to resolve the lookup.

If @server is also specified, it affects only the initial query for the root zone name servers.

+dnssec is set when +trace is set, to better emulate the default queries from a name server.

Note that the delv +ns option can also be used for tracing the resolution of a name from the root (see delv).

+tries=T: This option sets the number of times to try UDP and TCP queries to server to T instead of the default, 3. If T is less than or equal to zero, the number of tries is silently rounded up to 1.

+ttlid, +nottlid: This option displays [or does not display] the TTL when printing the record.

+ttlunits, +nottlunits: This option displays [or does not display] the TTL in friendly human-readable time units of s, m, h, d, and w, representing seconds, minutes, hours, days, and weeks. This implies +ttlid.

+unknownformat, +nounknownformat: This option prints all RDATA in unknown RR type presentation format (RFC 3597). The default is to print RDATA for known types in the type’s presentation format.

+vc, +novc: This option uses [or does not use] TCP when querying name servers. This alternate syntax to +tcp is provided for backwards compatibility. The vc stands for “virtual circuit.”

+yaml, +noyaml: When enabled, this option prints the responses (and, if +qr is in use, also the outgoing queries) in a detailed YAML format.

+zflag, +nozflag: This option sets [or does not set] the last unassigned DNS header flag in a DNS query. This flag is off by default.

Multiple Queries

The BIND 9 implementation of dig supports specifying multiple queries on the command line (in addition to supporting the -f batch file option). Each of those queries can be supplied with its own set of flags, options, and query options.

In this case, each query argument represents an individual query in the command-line syntax described above. Each consists of any of the standard options and flags, the name to be looked up, an optional query type and class, and any query options that should be applied to that query.

A global set of query options, which should be applied to all queries, can also be supplied. These global query options must precede the first tuple of name, class, type, options, flags, and query options supplied on the command line. Any global query options (except +cmd and +short options) can be overridden by a query-specific set of query options. For example:

dig +qr www.isc.org any -x 127.0.0.1 isc.org ns +noqr

shows how dig can be used from the command line to make three lookups: an ANY query for www.isc.org, a reverse lookup of 127.0.0.1, and a query for the NS records of isc.org. A global query option of +qr is applied, so that dig shows the initial query it made for each lookup. The final query has a local query option of +noqr which means that dig does not print the initial query when it looks up the NS records for isc.org.

Return Codes

dig return codes are:

0: DNS response received, including NXDOMAIN status
1: Usage error
8: Couldn’t open batch file
9: No reply from server
10: Internal error

Files

/etc/resolv.conf

${HOME}/.digrc

Bugs

There are probably too many query options.

dnssec-cds - change DS records for a child zone based on CDS/CDNSKEY

Synopsis

dnssec-cds [-a alg…] [-c class] [-D] {-d dsset-file} {-f child-file} [-i**[extension]] [-s** start-time] [-T ttl] [-u] [-v level] [-V] {domain}

Description

The dnssec-cds command changes DS records at a delegation point based on CDS or CDNSKEY records published in the child zone. If both CDS and CDNSKEY records are present in the child zone, the CDS is preferred. This enables a child zone to inform its parent of upcoming changes to its key-signing keys (KSKs); by polling periodically with dnssec-cds, the parent can keep the DS records up-to-date and enable automatic rolling of KSKs.

Two input files are required. The -f child-file option specifies a file containing the child’s CDS and/or CDNSKEY records, plus RRSIG and DNSKEY records so that they can be authenticated. The -d path option specifies the location of a file containing the current DS records. For example, this could be a dsset- file generated by dnssec-signzone, or the output of dnssec-dsfromkey, or the output of a previous run of dnssec-cds.

The dnssec-cds command uses special DNSSEC validation logic specified by RFC 7344. It requires that the CDS and/or CDNSKEY records be validly signed by a key represented in the existing DS records. This is typically the pre-existing KSK.

For protection against replay attacks, the signatures on the child records must not be older than they were on a previous run of dnssec-cds. Their age is obtained from the modification time of the dsset- file, or from the -s option.

To protect against breaking the delegation, dnssec-cds ensures that the DNSKEY RRset can be verified by every key algorithm in the new DS RRset, and that the same set of keys are covered by every DS digest type.

By default, replacement DS records are written to the standard output; with the -i option the input file is overwritten in place. The replacement DS records are the same as the existing records, when no change is required. The output can be empty if the CDS/CDNSKEY records specify that the child zone wants to be insecure.

Warning

Be careful not to delete the DS records when dnssec-cds fails!

Alternatively, :option`dnssec-cds -u` writes an nsupdate script to the standard output. The -u and -i options can be used together to maintain a dsset- file as well as emit an nsupdate script.

Options

-a algorithm

When converting CDS records to DS records, this option specifies the acceptable digest algorithms. This option can be repeated, so that multiple digest types are allowed. If none of the CDS records use an acceptable digest type, dnssec-cds will try to use CDNSKEY records instead; if there are no CDNSKEY records, it reports an error.

When converting CDNSKEY records to DS records, this option specifies the digest algorithm to use. It can be repeated, so that multiple DS records are created for each CDNSKEY records.

The algorithm must be one of SHA-1, SHA-256, or SHA-384. These values are case-insensitive, and the hyphen may be omitted. If no algorithm is specified, the default is SHA-256 only.

-c class: This option specifies the DNS class of the zones.

-D: This option generates DS records from CDNSKEY records if both CDS and CDNSKEY records are present in the child zone. By default CDS records are preferred.

-d path

This specifies the location of the parent DS records. The path can be the name of a file containing the DS records; if it is a directory, dnssec-cds looks for a dsset- file for the domain inside the directory.

To protect against replay attacks, child records are rejected if they were signed earlier than the modification time of the dsset- file. This can be adjusted with the -s option.

-f child-file

This option specifies the file containing the child’s CDS and/or CDNSKEY records, plus its DNSKEY records and the covering RRSIG records, so that they can be authenticated.

The examples below describe how to generate this file.

-i extension

This option updates the dsset- file in place, instead of writing DS records to the standard output.

There must be no space between the -i and the extension. If no extension is provided, the old dsset- is discarded. If an extension is present, a backup of the old dsset- file is kept with the extension appended to its filename.

To protect against replay attacks, the modification time of the dsset- file is set to match the signature inception time of the child records, provided that it is later than the file’s current modification time.

-s start-time

This option specifies the date and time after which RRSIG records become acceptable. This can be either an absolute or a relative time. An absolute start time is indicated by a number in YYYYMMDDHHMMSS notation; 20170827133700 denotes 13:37:00 UTC on August 27th, 2017. A time relative to the dsset- file is indicated with -N, which is N seconds before the file modification time. A time relative to the current time is indicated with now+N.

If no start-time is specified, the modification time of the dsset- file is used.

-T ttl: This option specifies a TTL to be used for new DS records. If not specified, the default is the TTL of the old DS records. If they had no explicit TTL, the new DS records also have no explicit TTL.

-u

This option writes an nsupdate script to the standard output, instead of printing the new DS reords. The output is empty if no change is needed.

Note: The TTL of new records needs to be specified: it can be done in the original dsset- file, with the -T option, or using the nsupdate ttl command.

-V: This option prints version information.

-v level: This option sets the debugging level. Level 1 is intended to be usefully verbose for general users; higher levels are intended for developers.

domain: This indicates the name of the delegation point/child zone apex.

Exit Status

The dnssec-cds command exits 0 on success, or non-zero if an error occurred.

If successful, the DS records may or may not need to be changed.

Examples

Before running dnssec-signzone, ensure that the delegations are up-to-date by running dnssec-cds on every dsset- file.

To fetch the child records required by dnssec-cds, invoke dig as in the script below. It is acceptable if the dig fails, since dnssec-cds performs all the necessary checking.

for f in dsset-*
do
    d=${f#dsset-}
    dig +dnssec +noall +answer $d DNSKEY $d CDNSKEY $d CDS |
    dnssec-cds -i -f /dev/stdin -d $f $d
done

When the parent zone is automatically signed by named, dnssec-cds can be used with nsupdate to maintain a delegation as follows. The dsset- file allows the script to avoid having to fetch and validate the parent DS records, and it maintains the replay attack protection time.

dig +dnssec +noall +answer $d DNSKEY $d CDNSKEY $d CDS |
dnssec-cds -u -i -f /dev/stdin -d $f $d |
nsupdate -l

dnssec-dsfromkey - DNSSEC DS RR generation tool

Synopsis

dnssec-dsfromkey [ -1 | -2 | -a alg ] [ -C ] [-T TTL] [-v level] [-K directory] {keyfile}

dnssec-dsfromkey [ -1 | -2 | -a alg ] [ -C ] [-T TTL] [-v level] [-c class] [-A] {-f file} [dnsname]

dnssec-dsfromkey [ -1 | -2 | -a alg ] [ -C ] [-T TTL] [-v level] [-c class] [-K directory] {-s} {dnsname}

dnssec-dsfromkey [ -h | -V ]

Description

The dnssec-dsfromkey command outputs DS (Delegation Signer) resource records (RRs), or CDS (Child DS) RRs with the -C option.

By default, only KSKs are converted (keys with flags = 257). The -A option includes ZSKs (flags = 256). Revoked keys are never included.

The input keys can be specified in a number of ways:

By default, dnssec-dsfromkey reads a key file named in the format Knnnn.+aaa+iiiii.key, as generated by dnssec-keygen.

With the -f file option, dnssec-dsfromkey reads keys from a zone file or partial zone file (which can contain just the DNSKEY records).

With the -s option, dnssec-dsfromkey reads a keyset- file, as generated by dnssec-keygen -C.

Options

-1: This option is an abbreviation for -a SHA1.

-2: This option is an abbreviation for -a SHA-256.

-a algorithm

This option specifies a digest algorithm to use when converting DNSKEY records to DS records. This option can be repeated, so that multiple DS records are created for each DNSKEY record.

The algorithm must be one of SHA-1, SHA-256, or SHA-384. These values are case-insensitive, and the hyphen may be omitted. If no algorithm is specified, the default is SHA-256.

-A: This option indicates that ZSKs are to be included when generating DS records. Without this option, only keys which have the KSK flag set are converted to DS records and printed. This option is only useful in -f zone file mode.

-c class: This option specifies the DNS class; the default is IN. This option is only useful in -s keyset or -f zone file mode.

-C: This option generates CDS records rather than DS records.

-f file

This option sets zone file mode, in which the final dnsname argument of dnssec-dsfromkey is the DNS domain name of a zone whose master file can be read from file. If the zone name is the same as file, then it may be omitted.

If file is -, then the zone data is read from the standard input. This makes it possible to use the output of the dig command as input, as in:

dig dnskey example.com | dnssec-dsfromkey -f - example.com

-h: This option prints usage information.

-K directory: This option tells BIND 9 to look for key files or keyset- files in directory.

-s: This option enables keyset mode, in which the final dnsname argument from dnssec-dsfromkey is the DNS domain name used to locate a keyset- file.

-T TTL: This option specifies the TTL of the DS records. By default the TTL is omitted.

-v level: This option sets the debugging level.

-V: This option prints version information.

Example

To build the SHA-256 DS RR from the Kexample.com.+003+26160 keyfile, issue the following command:

dnssec-dsfromkey -2 Kexample.com.+003+26160

The command returns something similar to:

example.com. IN DS 26160 5 2 3A1EADA7A74B8D0BA86726B0C227AA85AB8BBD2B2004F41A868A54F0C5EA0B94

Files

The keyfile can be designated by the key identification Knnnn.+aaa+iiiii or the full file name Knnnn.+aaa+iiiii.key, as generated by dnssec-keygen.

The keyset file name is built from the directory, the string keyset-, and the dnsname.

Caveat

A keyfile error may return “file not found,” even if the file exists.

dnssec-importkey - import DNSKEY records from external systems so they can be managed

Synopsis

dnssec-importkey [-K directory] [-L ttl] [-P date/offset] [-P sync date/offset] [-D date/offset] [-D sync date/offset] [-h] [-v level] [-V] {keyfile}

dnssec-importkey {-f filename} [-K directory] [-L ttl] [-P date/offset] [-P sync date/offset] [-D date/offset] [-D sync date/offset] [-h] [-v level] [-V] [dnsname]

Description

dnssec-importkey reads a public DNSKEY record and generates a pair of .key/.private files. The DNSKEY record may be read from an existing .key file, in which case a corresponding .private file is generated, or it may be read from any other file or from the standard input, in which case both .key and .private files are generated.

The newly created .private file does not contain private key data, and cannot be used for signing. However, having a .private file makes it possible to set publication (-P) and deletion (-D) times for the key, which means the public key can be added to and removed from the DNSKEY RRset on schedule even if the true private key is stored offline.

Options

-f filename

This option indicates the zone file mode. Instead of a public keyfile name, the argument is the DNS domain name of a zone master file, which can be read from filename. If the domain name is the same as filename, then it may be omitted.

If filename is set to "-", then the zone data is read from the standard input.

-K directory: This option sets the directory in which the key files are to reside.

-L ttl: This option sets the default TTL to use for this key when it is converted into a DNSKEY RR. This is the TTL used when the key is imported into a zone, unless there was already a DNSKEY RRset in place, in which case the existing TTL takes precedence. Setting the default TTL to 0 or none removes it from the key.

-h: This option emits a usage message and exits.

-v level: This option sets the debugging level.

-V: This option prints version information.

Timing Options

Dates can be expressed in the format YYYYMMDD or YYYYMMDDHHMMSS. (which is the format used inside key files), or ‘Day Mon DD HH:MM:SS YYYY’ (as printed by dnssec-settime -p), or UNIX epoch time (as printed by dnssec-settime -up), or the literal now.

The argument can be followed by + or - and an offset from the given time. The literal now can be omitted before an offset. The offset can be followed by one of the suffixes y, mo, w, d, h, or mi, so that it is computed in years (defined as 365 24-hour days, ignoring leap years), months (defined as 30 24-hour days), weeks, days, hours, or minutes, respectively. Without a suffix, the offset is computed in seconds.

To explicitly prevent a date from being set, use none, never, or unset.

All these formats are case-insensitive.

-P date/offset

This option sets the date on which a key is to be published to the zone. After that date, the key is included in the zone but is not used to sign it.

sync date/offset: This option sets the date on which CDS and CDNSKEY records that match this key are to be published to the zone.

-D date/offset

This option sets the date on which the key is to be deleted. After that date, the key is no longer included in the zone. (However, it may remain in the key repository.)

sync date/offset: This option sets the date on which the CDS and CDNSKEY records that match this key are to be deleted.

Files

A keyfile can be designed by the key identification Knnnn.+aaa+iiiii or the full file name Knnnn.+aaa+iiiii.key, as generated by dnssec-keygen.

dnssec-keyfromlabel - DNSSEC key generation tool

Synopsis

dnssec-keyfromlabel {-l label} [-3] [-a algorithm] [-A date/offset] [-c class] [-D date/offset] [-D sync date/offset] [-E engine] [-f flag] [-G] [-I date/offset] [-i interval] [-k] [-K directory] [-L ttl] [-n nametype] [-P date/offset] [-P sync date/offset] [-p protocol] [-R date/offset] [-S key] [-t type] [-v level] [-V] [-y] {name}

Description

dnssec-keyfromlabel generates a pair of key files that reference a key object stored in a cryptographic hardware service module (HSM). The private key file can be used for DNSSEC signing of zone data as if it were a conventional signing key created by dnssec-keygen, but the key material is stored within the HSM and the actual signing takes place there.

The name of the key is specified on the command line. This must match the name of the zone for which the key is being generated.

Options

-a algorithm

This option selects the cryptographic algorithm. The value of algorithm must be one of RSASHA1, NSEC3RSASHA1, RSASHA256, RSASHA512, ECDSAP256SHA256, ECDSAP384SHA384, ED25519, or ED448.

These values are case-insensitive. In some cases, abbreviations are supported, such as ECDSA256 for ECDSAP256SHA256 and ECDSA384 for ECDSAP384SHA384. If RSASHA1 is specified along with the -3 option, then NSEC3RSASHA1 is used instead.

This option is mandatory except when using the -S option, which copies the algorithm from the predecessory key.

Changed in version 9.12.0: The default value RSASHA1 for newly generated keys was removed.

-3: This option uses an NSEC3-capable algorithm to generate a DNSSEC key. If this option is used with an algorithm that has both NSEC and NSEC3 versions, then the NSEC3 version is used; for example, dnssec-keygen -3a RSASHA1 specifies the NSEC3RSASHA1 algorithm.

-E engine

This option specifies the cryptographic hardware to use.

When BIND 9 is built with OpenSSL, this needs to be set to the OpenSSL engine identifier that drives the cryptographic accelerator or hardware service module (usually pkcs11).

-l label

This option specifies the label for a key pair in the crypto hardware.

When BIND 9 is built with OpenSSL-based PKCS#11 support, the label is an arbitrary string that identifies a particular key. It may be preceded by an optional OpenSSL engine name, followed by a colon, as in pkcs11:keylabel.

-n nametype: This option specifies the owner type of the key. The value of nametype must either be ZONE (for a DNSSEC zone key (KEY/DNSKEY)), HOST or ENTITY (for a key associated with a host (KEY)), USER (for a key associated with a user (KEY)), or OTHER (DNSKEY). These values are case-insensitive.

-C: This option enables compatibility mode, which generates an old-style key, without any metadata. By default, dnssec-keyfromlabel includes the key’s creation date in the metadata stored with the private key; other dates may be set there as well, including publication date, activation date, etc. Keys that include this data may be incompatible with older versions of BIND; the -C option suppresses them.

-c class: This option indicates that the DNS record containing the key should have the specified class. If not specified, class IN is used.

-f flag: This option sets the specified flag in the flag field of the KEY/DNSKEY record. The only recognized flags are KSK (Key-Signing Key) and REVOKE.

-G: This option generates a key, but does not publish it or sign with it. This option is incompatible with -P and -A.

-h: This option prints a short summary of the options and arguments to dnssec-keyfromlabel.

-K directory: This option sets the directory in which the key files are to be written.

-k: This option generates KEY records rather than DNSKEY records.

-L ttl: This option sets the default TTL to use for this key when it is converted into a DNSKEY RR. This is the TTL used when the key is imported into a zone, unless there was already a DNSKEY RRset in place, in which case the existing TTL would take precedence. Setting the default TTL to 0 or none removes it.

-p protocol: This option sets the protocol value for the key. The protocol is a number between 0 and 255. The default is 3 (DNSSEC). Other possible values for this argument are listed in RFC 2535 and its successors.

-S key: This option generates a key as an explicit successor to an existing key. The name, algorithm, size, and type of the key are set to match the predecessor. The activation date of the new key is set to the inactivation date of the existing one. The publication date is set to the activation date minus the prepublication interval, which defaults to 30 days.

-t type: This option indicates the type of the key. type must be one of AUTHCONF, NOAUTHCONF, NOAUTH, or NOCONF. The default is AUTHCONF. AUTH refers to the ability to authenticate data, and CONF to the ability to encrypt data.

-v level: This option sets the debugging level.

-V: This option prints version information.

-y: This option allows DNSSEC key files to be generated even if the key ID would collide with that of an existing key, in the event of either key being revoked. (This is only safe to enable if RFC 5011 trust anchor maintenance is not used with either of the keys involved.)

Timing Options

Dates can be expressed in the format YYYYMMDD or YYYYMMDDHHMMSS (which is the format used inside key files), or ‘Day Mon DD HH:MM:SS YYYY’ (as printed by dnssec-settime -p), or UNIX epoch time (as printed by dnssec-settime -up), or the literal now.

The argument can be followed by + or - and an offset from the given time. The literal now can be omitted before an offset. The offset can be followed by one of the suffixes y, mo, w, d, h, or mi, so that it is computed in years (defined as 365 24-hour days, ignoring leap years), months (defined as 30 24-hour days), weeks, days, hours, or minutes, respectively. Without a suffix, the offset is computed in seconds.

To explicitly prevent a date from being set, use none, never, or unset.

All these formats are case-insensitive.

-P date/offset

This option sets the date on which a key is to be published to the zone. After that date, the key is included in the zone but is not used to sign it. If not set, and if the -G option has not been used, the default is the current date.

sync date/offset: This option sets the date on which CDS and CDNSKEY records that match this key are to be published to the zone.

-A date/offset: This option sets the date on which the key is to be activated. After that date, the key is included in the zone and used to sign it. If not set, and if the -G option has not been used, the default is the current date.

-R date/offset: This option sets the date on which the key is to be revoked. After that date, the key is flagged as revoked. It is included in the zone and is used to sign it.

-I date/offset: This option sets the date on which the key is to be retired. After that date, the key is still included in the zone, but it is not used to sign it.

-D date/offset

This option sets the date on which the key is to be deleted. After that date, the key is no longer included in the zone. (However, it may remain in the key repository.)

sync date/offset: This option sets the date on which the CDS and CDNSKEY records that match this key are to be deleted.

-i interval

This option sets the prepublication interval for a key. If set, then the publication and activation dates must be separated by at least this much time. If the activation date is specified but the publication date is not, the publication date defaults to this much time before the activation date; conversely, if the publication date is specified but not the activation date, activation is set to this much time after publication.

If the key is being created as an explicit successor to another key, then the default prepublication interval is 30 days; otherwise it is zero.

As with date offsets, if the argument is followed by one of the suffixes y, mo, w, d, h, or mi, the interval is measured in years, months, weeks, days, hours, or minutes, respectively. Without a suffix, the interval is measured in seconds.

Generated Key Files

When dnssec-keyfromlabel completes successfully, it prints a string of the form Knnnn.+aaa+iiiii to the standard output. This is an identification string for the key files it has generated.

nnnn is the key name.
aaa is the numeric representation of the algorithm.
iiiii is the key identifier (or footprint).

dnssec-keyfromlabel creates two files, with names based on the printed string. Knnnn.+aaa+iiiii.key contains the public key, and Knnnn.+aaa+iiiii.private contains the private key.

The .key file contains a DNS KEY record that can be inserted into a zone file (directly or with an $INCLUDE statement).

The .private file contains algorithm-specific fields. For obvious security reasons, this file does not have general read permission.

dnssec-keygen: DNSSEC key generation tool

Synopsis

dnssec-keygen [-3] [-A date/offset] [-a algorithm] [-b keysize] [-C] [-c class] [-D date/offset] [-d bits] [-D sync date/offset] [-E engine] [-f flag] [-F] [-G] [-h] [-I date/offset] [-i interval] [-K directory] [-k policy] [-L ttl] [-l file] [-n nametype] [-P date/offset] [-P sync date/offset] [-p protocol] [-q] [-R date/offset] [-S key] [-s strength] [-T rrtype] [-t type] [-V] [-v level] {name}

Description

dnssec-keygen generates keys for DNSSEC (Secure DNS), as defined in RFC 2535 and RFC 4034. It can also generate keys for use with TSIG (Transaction Signatures) as defined in RFC 2845, or TKEY (Transaction Key) as defined in RFC 2930.

The name of the key is specified on the command line. For DNSSEC keys, this must match the name of the zone for which the key is being generated.

Options

-3: This option uses an NSEC3-capable algorithm to generate a DNSSEC key. If this option is used with an algorithm that has both NSEC and NSEC3 versions, then the NSEC3 version is selected; for example, dnssec-keygen -3 -a RSASHA1 specifies the NSEC3RSASHA1 algorithm.

-a algorithm

This option selects the cryptographic algorithm. For DNSSEC keys, the value of algorithm must be one of RSASHA1, NSEC3RSASHA1, RSASHA256, RSASHA512, ECDSAP256SHA256, ECDSAP384SHA384, ED25519, or ED448.

These values are case-insensitive. In some cases, abbreviations are supported, such as ECDSA256 for ECDSAP256SHA256 and ECDSA384 for ECDSAP384SHA384. If RSASHA1 is specified along with the -3 option, NSEC3RSASHA1 is used instead.

This parameter must be specified except when using the -S option, which copies the algorithm from the predecessor key.

In prior releases, HMAC algorithms could be generated for use as TSIG keys, but that feature was removed in BIND 9.13.0. Use tsig-keygen to generate TSIG keys.

-b keysize

This option specifies the number of bits in the key. The choice of key size depends on the algorithm used: RSA keys must be between 1024 and 4096 bits; Diffie-Hellman keys must be between 128 and 4096 bits. Elliptic curve algorithms do not need this parameter.

If the key size is not specified, some algorithms have pre-defined defaults. For example, RSA keys for use as DNSSEC zone-signing keys have a default size of 1024 bits; RSA keys for use as key-signing keys (KSKs, generated with -f KSK) default to 2048 bits.

-C: This option enables compatibility mode, which generates an old-style key, without any timing metadata. By default, dnssec-keygen includes the key’s creation date in the metadata stored with the private key; other dates may be set there as well, including publication date, activation date, etc. Keys that include this data may be incompatible with older versions of BIND; the -C option suppresses them.

-c class: This option indicates that the DNS record containing the key should have the specified class. If not specified, class IN is used.

-d bits: This option specifies the key size in bits. For the algorithms RSASHA1, NSEC3RSASA1, RSASHA256, and RSASHA512 the key size must be between 1024 and 4096 bits; DH size is between 128 and 4096 bits. This option is ignored for algorithms ECDSAP256SHA256, ECDSAP384SHA384, ED25519, and ED448.

-E engine

This option specifies the cryptographic hardware to use, when applicable.

When BIND 9 is built with OpenSSL, this needs to be set to the OpenSSL engine identifier that drives the cryptographic accelerator or hardware service module (usually pkcs11).

-f flag: This option sets the specified flag in the flag field of the KEY/DNSKEY record. The only recognized flags are KSK (Key-Signing Key) and REVOKE.

-F: This options turns on FIPS (US Federal Information Processing Standards) mode if the underlying crytographic library supports running in FIPS mode.

-G: This option generates a key, but does not publish it or sign with it. This option is incompatible with -P and -A.

-h: This option prints a short summary of the options and arguments to dnssec-keygen.

-K directory: This option sets the directory in which the key files are to be written.

-k policy

This option creates keys for a specific dnssec-policy. If a policy uses multiple keys, dnssec-keygen generates multiple keys. This also creates a “.state” file to keep track of the key state.

This option creates keys according to the dnssec-policy configuration, hence it cannot be used at the same time as many of the other options that dnssec-keygen provides.

-L ttl: This option sets the default TTL to use for this key when it is converted into a DNSKEY RR. This is the TTL used when the key is imported into a zone, unless there was already a DNSKEY RRset in place, in which case the existing TTL takes precedence. If this value is not set and there is no existing DNSKEY RRset, the TTL defaults to the SOA TTL. Setting the default TTL to 0 or none is the same as leaving it unset.

-l file: This option provides a configuration file that contains a dnssec-policy statement (matching the policy set with -k).

-n nametype: This option specifies the owner type of the key. The value of nametype must either be ZONE (for a DNSSEC zone key (KEY/DNSKEY)), HOST or ENTITY (for a key associated with a host (KEY)), USER (for a key associated with a user (KEY)), or OTHER (DNSKEY). These values are case-insensitive. The default is ZONE for DNSKEY generation.

-p protocol: This option sets the protocol value for the generated key, for use with -T KEY. The protocol is a number between 0 and 255. The default is 3 (DNSSEC). Other possible values for this argument are listed in RFC 2535 and its successors.

-q: This option sets quiet mode, which suppresses unnecessary output, including progress indication. Without this option, when dnssec-keygen is run interactively to generate an RSA or DSA key pair, it prints a string of symbols to stderr indicating the progress of the key generation. A . indicates that a random number has been found which passed an initial sieve test; + means a number has passed a single round of the Miller-Rabin primality test; and a space ( ) means that the number has passed all the tests and is a satisfactory key.

-S key: This option creates a new key which is an explicit successor to an existing key. The name, algorithm, size, and type of the key are set to match the existing key. The activation date of the new key is set to the inactivation date of the existing one. The publication date is set to the activation date minus the prepublication interval, which defaults to 30 days.

-s strength: This option specifies the strength value of the key. The strength is a number between 0 and 15, and currently has no defined purpose in DNSSEC.

-T rrtype: This option specifies the resource record type to use for the key. rrtype must be either DNSKEY or KEY. The default is DNSKEY when using a DNSSEC algorithm, but it can be overridden to KEY for use with SIG(0).

-t type: This option indicates the type of the key for use with -T KEY. type must be one of AUTHCONF, NOAUTHCONF, NOAUTH, or NOCONF. The default is AUTHCONF. AUTH refers to the ability to authenticate data, and CONF to the ability to encrypt data.

-V: This option prints version information.

-v level: This option sets the debugging level.

Timing Options

Dates can be expressed in the format YYYYMMDD or YYYYMMDDHHMMSS (which is the format used inside key files), or ‘Day Mon DD HH:MM:SS YYYY’ (as printed by dnssec-settime -p), or UNIX epoch time (as printed by dnssec-settime -up), or the literal now.

The argument can be followed by + or - and an offset from the given time. The literal now can be omitted before an offset. The offset can be followed by one of the suffixes y, mo, w, d, h, or mi, so that it is computed in years (defined as 365 24-hour days, ignoring leap years), months (defined as 30 24-hour days), weeks, days, hours, or minutes, respectively. Without a suffix, the offset is computed in seconds.

To unset a date, use none, never, or unset.

-P date/offset

This option sets the date on which a key is to be published to the zone. After that date, the key is included in the zone but is not used to sign it. If not set, and if the -G option has not been used, the default is the current date.

sync date/offset: This option sets the date on which CDS and CDNSKEY records that match this key are to be published to the zone.

-A date/offset: This option sets the date on which the key is to be activated. After that date, the key is included in the zone and used to sign it. If not set, and if the -G option has not been used, the default is the current date. If set, and -P is not set, the publication date is set to the activation date minus the prepublication interval.

-R date/offset: This option sets the date on which the key is to be revoked. After that date, the key is flagged as revoked. It is included in the zone and is used to sign it.

-I date/offset: This option sets the date on which the key is to be retired. After that date, the key is still included in the zone, but it is not used to sign it.

-D date/offset

This option sets the date on which the key is to be deleted. After that date, the key is no longer included in the zone. (However, it may remain in the key repository.)

sync date/offset: This option sets the date on which the CDS and CDNSKEY records that match this key are to be deleted.

-i interval

This option sets the prepublication interval for a key. If set, then the publication and activation dates must be separated by at least this much time. If the activation date is specified but the publication date is not, the publication date defaults to this much time before the activation date; conversely, if the publication date is specified but not the activation date, activation is set to this much time after publication.

If the key is being created as an explicit successor to another key, then the default prepublication interval is 30 days; otherwise it is zero.

As with date offsets, if the argument is followed by one of the suffixes y, mo, w, d, h, or mi, the interval is measured in years, months, weeks, days, hours, or minutes, respectively. Without a suffix, the interval is measured in seconds.

Generated Keys

When dnssec-keygen completes successfully, it prints a string of the form Knnnn.+aaa+iiiii to the standard output. This is an identification string for the key it has generated.

nnnn is the key name.
aaa is the numeric representation of the algorithm.
iiiii is the key identifier (or footprint).

dnssec-keygen creates two files, with names based on the printed string. Knnnn.+aaa+iiiii.key contains the public key, and Knnnn.+aaa+iiiii.private contains the private key.

The .key file contains a DNSKEY or KEY record. When a zone is being signed by named or dnssec-signzone -S, DNSKEY records are included automatically. In other cases, the .key file can be inserted into a zone file manually or with an $INCLUDE statement.

The .private file contains algorithm-specific fields. For obvious security reasons, this file does not have general read permission.

Example

To generate an ECDSAP256SHA256 zone-signing key for the zone example.com, issue the command:

dnssec-keygen -a ECDSAP256SHA256 example.com

The command prints a string of the form:

Kexample.com.+013+26160

In this example, dnssec-keygen creates the files Kexample.com.+013+26160.key and Kexample.com.+013+26160.private.

To generate a matching key-signing key, issue the command:

dnssec-keygen -a ECDSAP256SHA256 -f KSK example.com

dnssec-revoke - set the REVOKED bit on a DNSSEC key

Synopsis

dnssec-revoke [-hr] [-v level] [-V] [-K directory] [-E engine] [-f] [-R] {keyfile}

Description

dnssec-revoke reads a DNSSEC key file, sets the REVOKED bit on the key as defined in RFC 5011, and creates a new pair of key files containing the now-revoked key.

Options

-h: This option emits a usage message and exits.

-K directory: This option sets the directory in which the key files are to reside.

-r: This option indicates to remove the original keyset files after writing the new keyset files.

-v level: This option sets the debugging level.

-V: This option prints version information.

-E engine

This option specifies the cryptographic hardware to use, when applicable.

When BIND 9 is built with OpenSSL, this needs to be set to the OpenSSL engine identifier that drives the cryptographic accelerator or hardware service module (usually pkcs11).

-f: This option indicates a forced overwrite and causes dnssec-revoke to write the new key pair, even if a file already exists matching the algorithm and key ID of the revoked key.

-R: This option prints the key tag of the key with the REVOKE bit set, but does not revoke the key.

dnssec-settime: set the key timing metadata for a DNSSEC key

Synopsis

dnssec-settime [-f] [-K directory] [-L ttl] [-P date/offset] [-P ds date/offset] [-P sync date/offset] [-A date/offset] [-R date/offset] [-I date/offset] [-D date/offset] [-D ds date/offset] [-D sync date/offset] [-S key] [-i interval] [-h] [-V] [-v level] [-E engine] {keyfile} [-s] [-g state] [-d state date/offset] [-k state date/offset] [-r state date/offset] [-z state date/offset]

Description

dnssec-settime reads a DNSSEC private key file and sets the key timing metadata as specified by the -P, -A, -R, -I, and -D options. The metadata can then be used by dnssec-signzone or other signing software to determine when a key is to be published, whether it should be used for signing a zone, etc.

If none of these options is set on the command line, dnssec-settime simply prints the key timing metadata already stored in the key.

When key metadata fields are changed, both files of a key pair (Knnnn.+aaa+iiiii.key and Knnnn.+aaa+iiiii.private) are regenerated.

Metadata fields are stored in the private file. A human-readable description of the metadata is also placed in comments in the key file. The private file’s permissions are always set to be inaccessible to anyone other than the owner (mode 0600).

When working with state files, it is possible to update the timing metadata in those files as well with -s. With this option, it is also possible to update key states with -d (DS), -k (DNSKEY), -r (RRSIG of KSK), or -z (RRSIG of ZSK). Allowed states are HIDDEN, RUMOURED, OMNIPRESENT, and UNRETENTIVE.

The goal state of the key can also be set with -g. This should be either HIDDEN or OMNIPRESENT, representing whether the key should be removed from the zone or published.

It is NOT RECOMMENDED to manipulate state files manually, except for testing purposes.

Options

-f: This option forces an update of an old-format key with no metadata fields. Without this option, dnssec-settime fails when attempting to update a legacy key. With this option, the key is recreated in the new format, but with the original key data retained. The key’s creation date is set to the present time. If no other values are specified, then the key’s publication and activation dates are also set to the present time.

-K directory: This option sets the directory in which the key files are to reside.

-L ttl: This option sets the default TTL to use for this key when it is converted into a DNSKEY RR. This is the TTL used when the key is imported into a zone, unless there was already a DNSKEY RRset in place, in which case the existing TTL takes precedence. If this value is not set and there is no existing DNSKEY RRset, the TTL defaults to the SOA TTL. Setting the default TTL to 0 or none removes it from the key.

-h: This option emits a usage message and exits.

-V: This option prints version information.

-v level: This option sets the debugging level.

-E engine

This option specifies the cryptographic hardware to use, when applicable.

When BIND 9 is built with OpenSSL, this needs to be set to the OpenSSL engine identifier that drives the cryptographic accelerator or hardware service module (usually pkcs11).

Timing Options

Dates can be expressed in the format YYYYMMDD or YYYYMMDDHHMMSS (which is the format used inside key files), or ‘Day Mon DD HH:MM:SS YYYY’ (as printed by dnssec-settime -p), or UNIX epoch time (as printed by dnssec-settime -up), or the literal now.

The argument can be followed by + or - and an offset from the given time. The literal now can be omitted before an offset. The offset can be followed by one of the suffixes y, mo, w, d, h, or mi, so that it is computed in years (defined as 365 24-hour days, ignoring leap years), months (defined as 30 24-hour days), weeks, days, hours, or minutes, respectively. Without a suffix, the offset is computed in seconds.

To unset a date, use none, never, or unset.

All these formats are case-insensitive.

-P date/offset

This option sets the date on which a key is to be published to the zone. After that date, the key is included in the zone but is not used to sign it.

ds date/offset: This option sets the date on which DS records that match this key have been seen in the parent zone.

sync date/offset: This option sets the date on which CDS and CDNSKEY records that match this key are to be published to the zone.

-A date/offset: This option sets the date on which the key is to be activated. After that date, the key is included in the zone and used to sign it.

-R date/offset: This option sets the date on which the key is to be revoked. After that date, the key is flagged as revoked. It is included in the zone and is used to sign it.

-I date/offset: This option sets the date on which the key is to be retired. After that date, the key is still included in the zone, but it is not used to sign it.

-D date/offset

This option sets the date on which the key is to be deleted. After that date, the key is no longer included in the zone. (However, it may remain in the key repository.)

ds date/offset: This option sets the date on which the DS records that match this key have been seen removed from the parent zone.

sync date/offset: This option sets the date on which the CDS and CDNSKEY records that match this key are to be deleted.

-S predecessor key: This option selects a key for which the key being modified is an explicit successor. The name, algorithm, size, and type of the predecessor key must exactly match those of the key being modified. The activation date of the successor key is set to the inactivation date of the predecessor. The publication date is set to the activation date minus the prepublication interval, which defaults to 30 days.

-i interval

This option sets the prepublication interval for a key. If set, then the publication and activation dates must be separated by at least this much time. If the activation date is specified but the publication date is not, the publication date defaults to this much time before the activation date; conversely, if the publication date is specified but not the activation date, activation is set to this much time after publication.

If the key is being created as an explicit successor to another key, then the default prepublication interval is 30 days; otherwise it is zero.

As with date offsets, if the argument is followed by one of the suffixes y, mo, w, d, h, or mi, the interval is measured in years, months, weeks, days, hours, or minutes, respectively. Without a suffix, the interval is measured in seconds.

Key State Options

To test dnssec-policy it may be necessary to construct keys with artificial state information; these options are used by the testing framework for that purpose, but should never be used in production.

Known key states are HIDDEN, RUMOURED, OMNIPRESENT, and UNRETENTIVE.

-s: This option indicates that when setting key timing data, the state file should also be updated.

-g state: This option sets the goal state for this key. Must be HIDDEN or OMNIPRESENT.

-d state date/offset: This option sets the DS state for this key as of the specified date, offset from the current date.

-k state date/offset: This option sets the DNSKEY state for this key as of the specified date, offset from the current date.

-r state date/offset: This option sets the RRSIG (KSK) state for this key as of the specified date, offset from the current date.

-z state date/offset: This option sets the RRSIG (ZSK) state for this key as of the specified date, offset from the current date.

Printing Options

dnssec-settime can also be used to print the timing metadata associated with a key.

-u: This option indicates that times should be printed in Unix epoch format.

-p C/P/Pds/Psync/A/R/I/D/Dds/Dsync/all: This option prints a specific metadata value or set of metadata values. The -p option may be followed by one or more of the following letters or strings to indicate which value or values to print: C for the creation date, P for the publication date, Pds` for the DS publication date, ``Psync for the CDS and CDNSKEY publication date, A for the activation date, R for the revocation date, I for the inactivation date, D for the deletion date, Dds for the DS deletion date, and Dsync for the CDS and CDNSKEY deletion date. To print all of the metadata, use all.

dnssec-signzone - DNSSEC zone signing tool

Synopsis

dnssec-signzone [-a] [-c class] [-d directory] [-D] [-E engine] [-e end-time] [-f output-file] [-F] [-g] [-G sync-records] [-h] [-i interval] [-I input-format] [-j jitter] [-K directory] [-k key] [-L serial] [-M maxttl] [-N soa-serial-format] [-o origin] [-O output-format] [-P] [-Q] [-q] [-R] [-S] [-s start-time] [-T ttl] [-t] [-u] [-v level] [-V] [-X extended end-time] [-x] [-z] [-3 salt] [-H iterations] [-A] {zonefile} [key…]

Description

dnssec-signzone signs a zone; it generates NSEC and RRSIG records and produces a signed version of the zone. The security status of delegations from the signed zone (that is, whether the child zones are secure) is determined by the presence or absence of a keyset file for each child zone.

Options

-a: This option verifies all generated signatures.

-c class: This option specifies the DNS class of the zone.

-C: This option sets compatibility mode, in which a keyset-zonename file is generated in addition to dsset-zonename when signing a zone, for use by older versions of dnssec-signzone.

-d directory: This option indicates the directory where BIND 9 should look for dsset- or keyset- files.

-D: This option indicates that only those record types automatically managed by dnssec-signzone, i.e., RRSIG, NSEC, NSEC3 and NSEC3PARAM records, should be included in the output. If smart signing (-S) is used, DNSKEY records are also included. The resulting file can be included in the original zone file with $INCLUDE. This option cannot be combined with -O raw or serial-number updating.

-E engine

This option specifies the hardware to use for cryptographic operations, such as a secure key store used for signing, when applicable.

When BIND 9 is built with OpenSSL, this needs to be set to the OpenSSL engine identifier that drives the cryptographic accelerator or hardware service module (usually pkcs11).

-F: This options turns on FIPS (US Federal Information Processing Standards) mode if the underlying crytographic library supports running in FIPS mode.

-g: This option indicates that DS records for child zones should be generated from a dsset- or keyset- file. Existing DS records are removed.

-G sync-records: This option indicates which CDS and CDNSKEY records should be generated. sync-records is a comma-separated string with the following allowed items: cdnskey, and cds:<digest-type>, where digest-type is an allowed algorithm such as SHA-256 (2), or SHA-384 (4). Only works in combination with smart signing (-S).

-K directory: This option specifies the directory to search for DNSSEC keys. If not specified, it defaults to the current directory.

-k key: This option tells BIND 9 to treat the specified key as a key-signing key, ignoring any key flags. This option may be specified multiple times.

-M maxttl: This option sets the maximum TTL for the signed zone. Any TTL higher than maxttl in the input zone is reduced to maxttl in the output. This provides certainty as to the largest possible TTL in the signed zone, which is useful to know when rolling keys. The maxttl is the longest possible time before signatures that have been retrieved by resolvers expire from resolver caches. Zones that are signed with this option should be configured to use a matching max-zone-ttl in named.conf. (Note: This option is incompatible with -D, because it modifies non-DNSSEC data in the output zone.)

-s start-time: This option specifies the date and time when the generated RRSIG records become valid. This can be either an absolute or relative time. An absolute start time is indicated by a number in YYYYMMDDHHMMSS notation; 20000530144500 denotes 14:45:00 UTC on May 30th, 2000. A relative start time is indicated by +N, which is N seconds from the current time. If no start-time is specified, the current time minus 1 hour (to allow for clock skew) is used.

-e end-time: This option specifies the date and time when the generated RRSIG records expire. As with start-time, an absolute time is indicated in YYYYMMDDHHMMSS notation. A time relative to the start time is indicated with +N, which is N seconds from the start time. A time relative to the current time is indicated with now+N. If no end-time is specified, 30 days from the start time is the default. end-time must be later than start-time.

-X extended end-time

This option specifies the date and time when the generated RRSIG records for the DNSKEY RRset expire. This is to be used in cases when the DNSKEY signatures need to persist longer than signatures on other records; e.g., when the private component of the KSK is kept offline and the KSK signature is to be refreshed manually.

As with end-time, an absolute time is indicated in YYYYMMDDHHMMSS notation. A time relative to the start time is indicated with +N, which is N seconds from the start time. A time relative to the current time is indicated with now+N. If no extended end-time is specified, the value of end-time is used as the default. (end-time, in turn, defaults to 30 days from the start time.) extended end-time must be later than start-time.

-f output-file: This option indicates the name of the output file containing the signed zone. The default is to append .signed to the input filename. If output-file is set to -, then the signed zone is written to the standard output, with a default output format of full.

-h: This option prints a short summary of the options and arguments to dnssec-signzone.

-V: This option prints version information.

-i interval

This option indicates that, when a previously signed zone is passed as input, records may be re-signed. The interval option specifies the cycle interval as an offset from the current time, in seconds. If a RRSIG record expires after the cycle interval, it is retained; otherwise, it is considered to be expiring soon and it is replaced.

The default cycle interval is one quarter of the difference between the signature end and start times. So if neither end-time nor start-time is specified, dnssec-signzone generates signatures that are valid for 30 days, with a cycle interval of 7.5 days. Therefore, if any existing RRSIG records are due to expire in less than 7.5 days, they are replaced.

-I input-format: This option sets the format of the input zone file. Possible formats are text (the default), and raw. This option is primarily intended to be used for dynamic signed zones, so that the dumped zone file in a non-text format containing updates can be signed directly. This option is not useful for non-dynamic zones.

-j jitter

When signing a zone with a fixed signature lifetime, all RRSIG records issued at the time of signing expire simultaneously. If the zone is incrementally signed, i.e., a previously signed zone is passed as input to the signer, all expired signatures must be regenerated at approximately the same time. The jitter option specifies a jitter window that is used to randomize the signature expire time, thus spreading incremental signature regeneration over time.

Signature lifetime jitter also, to some extent, benefits validators and servers by spreading out cache expiration, i.e., if large numbers of RRSIGs do not expire at the same time from all caches, there is less congestion than if all validators need to refetch at around the same time.

-L serial: When writing a signed zone to “raw” format, this option sets the “source serial” value in the header to the specified serial number. (This is expected to be used primarily for testing purposes.)

-n ncpus: This option specifies the number of threads to use. By default, one thread is started for each detected CPU.

-N soa-serial-format

This option sets the SOA serial number format of the signed zone. Possible formats are keep (the default), increment, unixtime, and date.

keep: This format indicates that the SOA serial number should not be modified.
increment: This format increments the SOA serial number using RFC 1982 arithmetic.
unixtime: This format sets the SOA serial number to the number of seconds since the beginning of the Unix epoch, unless the serial number is already greater than or equal to that value, in which case it is simply incremented by one.
date: This format sets the SOA serial number to today’s date, in YYYYMMDDNN format, unless the serial number is already greater than or equal to that value, in which case it is simply incremented by one.

-o origin: This option sets the zone origin. If not specified, the name of the zone file is assumed to be the origin.

-O output-format: This option sets the format of the output file containing the signed zone. Possible formats are text (the default), which is the standard textual representation of the zone; full, which is text output in a format suitable for processing by external scripts; and raw and raw=N, which store the zone in binary formats for rapid loading by named. raw=N specifies the format version of the raw zone file: if N is 0, the raw file can be read by any version of named; if N is 1, the file can be read by release 9.9.0 or higher. The default is 1.

-P

This option disables post-sign verification tests.

The post-sign verification tests ensure that for each algorithm in use there is at least one non-revoked self-signed KSK key, that all revoked KSK keys are self-signed, and that all records in the zone are signed by the algorithm. This option skips these tests.

-Q

This option removes signatures from keys that are no longer active.

Normally, when a previously signed zone is passed as input to the signer, and a DNSKEY record has been removed and replaced with a new one, signatures from the old key that are still within their validity period are retained. This allows the zone to continue to validate with cached copies of the old DNSKEY RRset. The -Q option forces dnssec-signzone to remove signatures from keys that are no longer active. This enables ZSK rollover using the procedure described in RFC 4641#4.2.1.1 (“Pre-Publish Key Rollover”).

-q: This option enables quiet mode, which suppresses unnecessary output. Without this option, when dnssec-signzone is run it prints three pieces of information to standard output: the number of keys in use; the algorithms used to verify the zone was signed correctly and other status information; and the filename containing the signed zone. With the option that output is suppressed, leaving only the filename.

-R

This option removes signatures from keys that are no longer published.

This option is similar to -Q, except it forces dnssec-signzone to remove signatures from keys that are no longer published. This enables ZSK rollover using the procedure described in RFC 4641#4.2.1.2 (“Double Signature Zone Signing Key Rollover”).

-S

This option enables smart signing, which instructs dnssec-signzone to search the key repository for keys that match the zone being signed, and to include them in the zone if appropriate.

When a key is found, its timing metadata is examined to determine how it should be used, according to the following rules. Each successive rule takes priority over the prior ones:

If no timing metadata has been set for the key, the key is published in the zone and used to sign the zone.

If the key’s publication date is set and is in the past, the key is published in the zone.

If the key’s activation date is set and is in the past, the key is published (regardless of publication date) and used to sign the zone.

If the key’s revocation date is set and is in the past, and the key is published, then the key is revoked, and the revoked key is used to sign the zone.

If either the key’s unpublication or deletion date is set and in the past, the key is NOT published or used to sign the zone, regardless of any other metadata.

If the key’s sync publication date is set and is in the past, synchronization records (type CDS and/or CDNSKEY) are created.

If the key’s sync deletion date is set and is in the past, synchronization records (type CDS and/or CDNSKEY) are removed.

-T ttl: This option specifies a TTL to be used for new DNSKEY records imported into the zone from the key repository. If not specified, the default is the TTL value from the zone’s SOA record. This option is ignored when signing without -S, since DNSKEY records are not imported from the key repository in that case. It is also ignored if there are any pre-existing DNSKEY records at the zone apex, in which case new records’ TTL values are set to match them, or if any of the imported DNSKEY records had a default TTL value. In the event of a conflict between TTL values in imported keys, the shortest one is used.

-t: This option prints statistics at completion.

-u: This option updates the NSEC/NSEC3 chain when re-signing a previously signed zone. With this option, a zone signed with NSEC can be switched to NSEC3, or a zone signed with NSEC3 can be switched to NSEC or to NSEC3 with different parameters. Without this option, dnssec-signzone retains the existing chain when re-signing.

-v level: This option sets the debugging level.

-x: This option indicates that BIND 9 should only sign the DNSKEY, CDNSKEY, and CDS RRsets with key-signing keys, and should omit signatures from zone-signing keys.

-z: This option indicates that BIND 9 should ignore the KSK flag on keys when determining what to sign. This causes KSK-flagged keys to sign all records, not just the DNSKEY RRset.

-3 salt: This option generates an NSEC3 chain with the given hex-encoded salt. A dash (-) can be used to indicate that no salt is to be used when generating the NSEC3 chain.

Note

-3 - is the recommended configuration. Adding salt provides no practical benefits.

-H iterations: This option indicates that, when generating an NSEC3 chain, BIND 9 should use this many iterations. The default is 0.

Warning

Values greater than 0 cause interoperability issues and also increase the risk of CPU-exhausting DoS attacks.

-A: This option indicates that, when generating an NSEC3 chain, BIND 9 should set the OPTOUT flag on all NSEC3 records and should not generate NSEC3 records for insecure delegations.

Warning

Do not use this option unless all its implications are fully understood. This option is intended only for extremely large zones (comparable to com.) with sparse secure delegations.

-AA: This option turns the OPTOUT flag off for all records. This is useful when using the -u option to modify an NSEC3 chain which previously had OPTOUT set.

zonefile: This option sets the file containing the zone to be signed.

key: This option specifies which keys should be used to sign the zone. If no keys are specified, the zone is examined for DNSKEY records at the zone apex. If these records are found and there are matching private keys in the current directory, they are used for signing.

Example

The following command signs the example.com zone with the ECDSAP256SHA256 key generated by dnssec-keygen (Kexample.com.+013+17247). Because the -S option is not being used, the zone’s keys must be in the master file (db.example.com). This invocation looks for dsset files in the current directory, so that DS records can be imported from them (-g).

% dnssec-signzone -g -o example.com db.example.com \
Kexample.com.+013+17247
db.example.com.signed
%

In the above example, dnssec-signzone creates the file db.example.com.signed. This file should be referenced in a zone statement in the named.conf file.

This example re-signs a previously signed zone with default parameters. The private keys are assumed to be in the current directory.

% cp db.example.com.signed db.example.com
% dnssec-signzone -o example.com db.example.com
db.example.com.signed
%

dnssec-verify - DNSSEC zone verification tool

Synopsis

dnssec-verify [-c class] [-E engine] [-I input-format] [-o origin] [-q] [-v level] [-V] [-x] [-z] {zonefile}

Description

dnssec-verify verifies that a zone is fully signed for each algorithm found in the DNSKEY RRset for the zone, and that the NSEC/NSEC3 chains are complete.

Options

-c class: This option specifies the DNS class of the zone.

-E engine

This option specifies the cryptographic hardware to use, when applicable.

When BIND 9 is built with OpenSSL, this needs to be set to the OpenSSL engine identifier that drives the cryptographic accelerator or hardware service module (usually pkcs11).

-I input-format: This option sets the format of the input zone file. Possible formats are text (the default) and raw. This option is primarily intended to be used for dynamic signed zones, so that the dumped zone file in a non-text format containing updates can be verified independently. This option is not useful for non-dynamic zones.

-o origin: This option indicates the zone origin. If not specified, the name of the zone file is assumed to be the origin.

-v level: This option sets the debugging level.

-V: This option prints version information.

-q: This option sets quiet mode, which suppresses output. Without this option, when dnssec-verify is run it prints to standard output the number of keys in use, the algorithms used to verify the zone was signed correctly, and other status information. With this option, all non-error output is suppressed, and only the exit code indicates success.

-x: This option verifies only that the DNSKEY RRset is signed with key-signing keys. Without this flag, it is assumed that the DNSKEY RRset is signed by all active keys. When this flag is set, it is not an error if the DNSKEY RRset is not signed by zone-signing keys. This corresponds to the -x option in dnssec-signzone.

-z

This option indicates that the KSK flag on the keys should be ignored when determining whether the zone is correctly signed. Without this flag, it is assumed that there is a non-revoked, self-signed DNSKEY with the KSK flag set for each algorithm, and that RRsets other than DNSKEY RRset are signed with a different DNSKEY without the KSK flag set.

With this flag set, BIND 9 only requires that for each algorithm, there be at least one non-revoked, self-signed DNSKEY, regardless of the KSK flag state, and that other RRsets be signed by a non-revoked key for the same algorithm that includes the self-signed key; the same key may be used for both purposes. This corresponds to the -z option in dnssec-signzone.

zonefile: This option indicates the file containing the zone to be signed.

dnstap-read - print dnstap data in human-readable form

Synopsis

dnstap-read [-m] [-p] [-x] [-y] {file}

Description

dnstap-read reads dnstap data from a specified file and prints it in a human-readable format. By default, dnstap data is printed in a short summary format, but if the -y option is specified, a longer and more detailed YAML format is used.

Options

-m: This option indicates trace memory allocations, and is used for debugging memory leaks.

-p: This option prints the text form of the DNS message that was encapsulated in the dnstap frame, after printing the dnstap data.

-t: This option prints long timestamps with millisecond precision.

-x: This option prints a hex dump of the wire form of the DNS message that was encapsulated in the dnstap frame, after printing the dnstap data.

-y: This option prints dnstap data in a detailed YAML format.

filter-aaaa.so - filter AAAA in DNS responses when A is present

Synopsis

plugin query “filter-aaaa.so” [{ parameters }];

Description

filter-aaaa.so is a query plugin module for named, enabling named to omit some IPv6 addresses when responding to clients.

Until BIND 9.12, this feature was implemented natively in named and enabled with the filter-aaaa ACL and the filter-aaaa-on-v4 and filter-aaaa-on-v6 options. These options are no longer available in named.conf but can be passed as parameters to the filter-aaaa.so plugin, for example:

plugin query "filter-aaaa.so" {
        filter-aaaa-on-v4 yes;
        filter-aaaa-on-v6 yes;
        filter-aaaa { 192.0.2.1; 2001:db8:2::1; };
};

This module is intended to aid transition from IPv4 to IPv6 by withholding IPv6 addresses from DNS clients which are not connected to the IPv6 Internet, when the name being looked up has an IPv4 address available. Use of this module is not recommended unless absolutely necessary.

Note: This mechanism can erroneously cause other servers not to give AAAA records to their clients. If a recursing server with both IPv6 and IPv4 network connections queries an authoritative server using this mechanism via IPv4, it is denied AAAA records even if its client is using IPv6.

Options

filter-aaaa

This option specifies a list of client addresses for which AAAA filtering is to be applied. The default is any.

filter-aaaa-on-v4

If set to yes, this option indicates that the DNS client is at an IPv4 address, in filter-aaaa. If the response does not include DNSSEC signatures, then all AAAA records are deleted from the response. This filtering applies to all responses, not only authoritative ones.

If set to break-dnssec, then AAAA records are deleted even when DNSSEC is enabled. As suggested by the name, this causes the response to fail to verify, because the DNSSEC protocol is designed to detect deletions.

This mechanism can erroneously cause other servers not to give AAAA records to their clients. If a recursing server with both IPv6 and IPv4 network connections queries an authoritative server using this mechanism via IPv4, it is denied AAAA records even if its client is using IPv6.

filter-aaaa-on-v6

This option is identical to filter-aaaa-on-v4, except that it filters AAAA responses to queries from IPv6 clients instead of IPv4 clients. To filter all responses, set both options to yes.

host - DNS lookup utility

Synopsis

host [-aACdlnrsTUwv] [-c class] [-N ndots] [-p port] [-R number] [-t type] [-W wait] [-m flag] [ [-4] | [-6] ] [-v] [-V] {name} [server]

Description

host is a simple utility for performing DNS lookups. It is normally used to convert names to IP addresses and vice versa. When no arguments or options are given, host prints a short summary of its command-line arguments and options.

name is the domain name that is to be looked up. It can also be a dotted-decimal IPv4 address or a colon-delimited IPv6 address, in which case host by default performs a reverse lookup for that address. server is an optional argument which is either the name or IP address of the name server that host should query instead of the server or servers listed in /etc/resolv.conf.

Options

-4: This option specifies that only IPv4 should be used for query transport. See also the -6 option.

-6: This option specifies that only IPv6 should be used for query transport. See also the -4 option.

-a: The -a (“all”) option is normally equivalent to -v -t ANY. It also affects the behavior of the -l list zone option.

-A: The -A (“almost all”) option is equivalent to -a, except that RRSIG, NSEC, and NSEC3 records are omitted from the output.

-c class: This option specifies the query class, which can be used to lookup HS (Hesiod) or CH (Chaosnet) class resource records. The default class is IN (Internet).

-C: This option indicates that named should check consistency, meaning that host queries the SOA records for zone name from all the listed authoritative name servers for that zone. The list of name servers is defined by the NS records that are found for the zone.

-d: This option prints debugging traces, and is equivalent to the -v verbose option.

-l

This option tells named to list the zone, meaning the host command performs a zone transfer of zone name and prints out the NS, PTR, and address records (A/AAAA).

Together, the -l -a options print all records in the zone.

-N ndots: This option specifies the number of dots (ndots) that have to be in name for it to be considered absolute. The default value is that defined using the ndots statement in /etc/resolv.conf, or 1 if no ndots statement is present. Names with fewer dots are interpreted as relative names, and are searched for in the domains listed in the search or domain directive in /etc/resolv.conf.

-p port: This option specifies the port to query on the server. The default is 53.

-r: This option specifies a non-recursive query; setting this option clears the RD (recursion desired) bit in the query. This means that the name server receiving the query does not attempt to resolve name. The -r option enables host to mimic the behavior of a name server by making non-recursive queries, and expecting to receive answers to those queries that can be referrals to other name servers.

-R number: This option specifies the number of retries for UDP queries. If number is negative or zero, the number of retries is silently set to 1. The default value is 1, or the value of the attempts option in /etc/resolv.conf, if set.

-s: This option tells named not to send the query to the next nameserver if any server responds with a SERVFAIL response, which is the reverse of normal stub resolver behavior.

-t type

This option specifies the query type. The type argument can be any recognized query type: CNAME, NS, SOA, TXT, DNSKEY, AXFR, etc.

When no query type is specified, host automatically selects an appropriate query type. By default, it looks for A, AAAA, and MX records. If the -C option is given, queries are made for SOA records. If name is a dotted-decimal IPv4 address or colon-delimited IPv6 address, host queries for PTR records.

If a query type of IXFR is chosen, the starting serial number can be specified by appending an equals sign (=), followed by the starting serial number, e.g., -t IXFR=12345678.

-T, -U: This option specifies TCP or UDP. By default, host uses UDP when making queries; the -T option makes it use a TCP connection when querying the name server. TCP is automatically selected for queries that require it, such as zone transfer (AXFR) requests. Type ANY queries default to TCP, but can be forced to use UDP initially via -U.

-m flag: This option sets memory usage debugging: the flag can be record, usage, or trace. The -m option can be specified more than once to set multiple flags.

-v: This option sets verbose output, and is equivalent to the -d debug option. Verbose output can also be enabled by setting the debug option in /etc/resolv.conf.

-V: This option prints the version number and exits.

-w: This option sets “wait forever”: the query timeout is set to the maximum possible. See also the -W option.

-W wait

This options sets the length of the wait timeout, indicating that named should wait for up to wait seconds for a reply. If wait is less than 1, the wait interval is set to 1 second.

By default, host waits for 5 seconds for UDP responses and 10 seconds for TCP connections. These defaults can be overridden by the timeout option in /etc/resolv.conf.

IDN Support

If host has been built with IDN (internationalized domain name) support, it can accept and display non-ASCII domain names. host appropriately converts character encoding of a domain name before sending a request to a DNS server or displaying a reply from the server. To turn off IDN support, define the IDN_DISABLE environment variable. IDN support is disabled if the variable is set when host runs.

Files

/etc/resolv.conf

mdig - DNS pipelined lookup utility

Synopsis

mdig {@server} [-f filename] [-h] [-v] [ [-4] | [-6] ] [-m] [-b address] [-p port#] [-c class] [-t type] [-i] [-x addr] [plusopt…]

mdig {-h}

mdig [@server] {global-opt…} { {local-opt…} {query} …}

Description

mdig is a multiple/pipelined query version of dig: instead of waiting for a response after sending each query, it begins by sending all queries. Responses are displayed in the order in which they are received, not in the order the corresponding queries were sent.

mdig options are a subset of the dig options, and are divided into “anywhere options,” which can occur anywhere, “global options,” which must occur before the query name (or they are ignored with a warning), and “local options,” which apply to the next query on the command line.

The @server option is a mandatory global option. It is the name or IP address of the name server to query. (Unlike dig, this value is not retrieved from /etc/resolv.conf.) It can be an IPv4 address in dotted-decimal notation, an IPv6 address in colon-delimited notation, or a hostname. When the supplied server argument is a hostname, mdig resolves that name before querying the name server.

mdig provides a number of query options which affect the way in which lookups are made and the results displayed. Some of these set or reset flag bits in the query header, some determine which sections of the answer get printed, and others determine the timeout and retry strategies.

Each query option is identified by a keyword preceded by a plus sign (+). Some keywords set or reset an option. These may be preceded by the string no to negate the meaning of that keyword. Other keywords assign values to options like the timeout interval. They have the form +keyword=value.

Anywhere Options

-f: This option makes mdig operate in batch mode by reading a list of lookup requests to process from the file filename. The file contains a number of queries, one per line. Each entry in the file should be organized in the same way they would be presented as queries to mdig using the command-line interface.

-h: This option causes mdig to print detailed help information, with the full list of options, and exit.

-v: This option causes mdig to print the version number and exit.

Global Options

-4: This option forces mdig to only use IPv4 query transport.

-6: This option forces mdig to only use IPv6 query transport.

-b address: This option sets the source IP address of the query to address. This must be a valid address on one of the host’s network interfaces or “0.0.0.0” or “::”. An optional port may be specified by appending “#<port>”

-m: This option enables memory usage debugging.

-p port#: This option is used when a non-standard port number is to be queried. port# is the port number that mdig sends its queries to, instead of the standard DNS port number 53. This option is used to test a name server that has been configured to listen for queries on a non-standard port number.

The global query options are:

+additional, +noadditional: This option displays [or does not display] the additional section of a reply. The default is to display it.

+all, +noall: This option sets or clears all display flags.

+answer, +noanswer: This option displays [or does not display] the answer section of a reply. The default is to display it.

+authority, +noauthority: This option displays [or does not display] the authority section of a reply. The default is to display it.

+besteffort, +nobesteffort: This option attempts to display [or does not display] the contents of messages which are malformed. The default is to not display malformed answers.

+burst: This option delays queries until the start of the next second.

+cl, +nocl: This option displays [or does not display] the CLASS when printing the record.

+comments, +nocomments: This option toggles the display of comment lines in the output. The default is to print comments.

+continue, +nocontinue: This option toggles continuation on errors (e.g. timeouts).

+crypto, +nocrypto: This option toggles the display of cryptographic fields in DNSSEC records. The contents of these fields are unnecessary to debug most DNSSEC validation failures and removing them makes it easier to see the common failures. The default is to display the fields. When omitted, they are replaced by the string “[omitted]”; in the DNSKEY case, the key ID is displayed as the replacement, e.g., [ key id = value ].

+multiline, +nomultiline: This option toggles printing of records, like the SOA records, in a verbose multi-line format with human-readable comments. The default is to print each record on a single line, to facilitate machine parsing of the mdig output.

+question, +noquestion: This option prints [or does not print] the question section of a query when an answer is returned. The default is to print the question section as a comment.

+rrcomments, +norrcomments: This option toggles the display of per-record comments in the output (for example, human-readable key information about DNSKEY records). The default is not to print record comments unless multiline mode is active.

+short, +noshort: This option provides [or does not provide] a terse answer. The default is to print the answer in a verbose form.

+split=W: This option splits long hex- or base64-formatted fields in resource records into chunks of W characters (where W is rounded up to the nearest multiple of 4). +nosplit or +split=0 causes fields not to be split. The default is 56 characters, or 44 characters when multiline mode is active.

+tcp, +notcp: This option uses [or does not use] TCP when querying name servers. The default behavior is to use UDP.

+ttlid, +nottlid: This option displays [or does not display] the TTL when printing the record.

+ttlunits, +nottlunits: This option displays [or does not display] the TTL in friendly human-readable time units of “s”, “m”, “h”, “d”, and “w”, representing seconds, minutes, hours, days, and weeks. This implies +ttlid.

+vc, +novc: This option uses [or does not use] TCP when querying name servers. This alternate syntax to +tcp is provided for backwards compatibility. The vc stands for “virtual circuit”.

Local Options

-c class: This option sets the query class to class. It can be any valid query class which is supported in BIND 9. The default query class is “IN”.

-t type: This option sets the query type to type. It can be any valid query type which is supported in BIND 9. The default query type is “A”, unless the -x option is supplied to indicate a reverse lookup with the “PTR” query type.

-x addr: Reverse lookups - mapping addresses to names - are simplified by this option. addr is an IPv4 address in dotted-decimal notation, or a colon-delimited IPv6 address. mdig automatically performs a lookup for a query name like 11.12.13.10.in-addr.arpa and sets the query type and class to PTR and IN respectively. By default, IPv6 addresses are looked up using nibble format under the IP6.ARPA domain.

The local query options are:

+aaflag, +noaaflag: This is a synonym for +aaonly, +noaaonly.

+aaonly, +noaaonly: This sets the aa flag in the query.

+adflag, +noadflag: This sets [or does not set] the AD (authentic data) bit in the query. This requests the server to return whether all of the answer and authority sections have all been validated as secure, according to the security policy of the server. AD=1 indicates that all records have been validated as secure and the answer is not from a OPT-OUT range. AD=0 indicates that some part of the answer was insecure or not validated. This bit is set by default.

+bufsize=B: This sets the UDP message buffer size advertised using EDNS0 to B bytes. The maximum and minimum sizes of this buffer are 65535 and 0 respectively. Values outside this range are rounded up or down appropriately. Values other than zero cause a EDNS query to be sent.

+cdflag, +nocdflag: This sets [or does not set] the CD (checking disabled) bit in the query. This requests the server to not perform DNSSEC validation of responses.

+cookie=####, +nocookie: This sends [or does not send] a COOKIE EDNS option, with an optional value. Replaying a COOKIE from a previous response allows the server to identify a previous client. The default is +nocookie.

+dnssec, +nodnssec: This requests that DNSSEC records be sent by setting the DNSSEC OK (DO) bit in the OPT record in the additional section of the query.

+edns[=#], +noedns: This specifies [or does not specify] the EDNS version to query with. Valid values are 0 to 255. Setting the EDNS version causes an EDNS query to be sent. +noedns clears the remembered EDNS version. EDNS is set to 0 by default.

+ednsflags[=#], +noednsflags: This sets the must-be-zero EDNS flag bits (Z bits) to the specified value. Decimal, hex, and octal encodings are accepted. Setting a named flag (e.g. DO) is silently ignored. By default, no Z bits are set.

+ednsopt[=code[:value]], +noednsopt: This specifies [or does not specify] an EDNS option with code point code and an optional payload of value as a hexadecimal string. +noednsopt clears the EDNS options to be sent.

+expire, +noexpire: This toggles sending of an EDNS Expire option.

+nsid, +nonsid: This toggles inclusion of an EDNS name server ID request when sending a query.

+recurse, +norecurse: This toggles the setting of the RD (recursion desired) bit in the query. This bit is set by default, which means mdig normally sends recursive queries.

+retry=T: This sets the number of times to retry UDP queries to server to T instead of the default, 2. Unlike +tries, this does not include the initial query.

+subnet=addr[/prefix-length], +nosubnet: This sends [or does not send] an EDNS Client Subnet option with the specified IP address or network prefix.

mdig +subnet=0.0.0.0/0, or simply mdig +subnet=0: This sends an EDNS client-subnet option with an empty address and a source prefix-length of zero, which signals a resolver that the client’s address information must not be used when resolving this query.

+timeout=T: This sets the timeout for a query to T seconds. The default timeout is 5 seconds for UDP transport and 10 for TCP. An attempt to set T to less than 1 results in a query timeout of 1 second being applied.

+tries=T: This sets the number of times to try UDP queries to server to T instead of the default, 3. If T is less than or equal to zero, the number of tries is silently rounded up to 1.

+udptimeout=T: This sets the timeout between UDP query retries to T.

+unknownformat, +nounknownformat: This prints [or does not print] all RDATA in unknown RR-type presentation format (see RFC 3597). The default is to print RDATA for known types in the type’s presentation format.

+yaml, +noyaml: This toggles printing of the responses in a detailed YAML format.

+zflag, +nozflag: This sets [or does not set] the last unassigned DNS header flag in a DNS query. This flag is off by default.

named-checkconf - named configuration file syntax checking tool

Synopsis

named-checkconf [-achjlvz] [-p [-x ]] [-t directory] {filename}

Description

named-checkconf checks the syntax, but not the semantics, of a named configuration file. The file, along with all files included by it, is parsed and checked for syntax errors. If no file is specified, /usr/local/etc/named.conf is read by default.

Note: files that named reads in separate parser contexts, such as rndc.conf or rndc.key, are not automatically read by named-checkconf. Configuration errors in these files may cause named to fail to run, even if named-checkconf was successful. However, named-checkconf can be run on these files explicitly.

Options

-a: Don’t check the dnssec-policy’s DNSSEC key algorithms against those supported by the crypto provider. This is useful when checking a named.conf intended to be run on another machine with possibly a different set of supported DNSSEC key algorithms.

-h: This option prints the usage summary and exits.

-j: When loading a zonefile, this option instructs named to read the journal if it exists.

-l: This option lists all the configured zones. Each line of output contains the zone name, class (e.g. IN), view, and type (e.g. primary or secondary).

-c: This option specifies that only the “core” configuration should be checked. This suppresses the loading of plugin modules, and causes all parameters to plugin statements to be ignored.

-i: This option ignores warnings on deprecated options.

-p: This option prints out the named.conf and included files in canonical form if no errors were detected. See also the -x option.

-t directory: This option instructs named to chroot to directory, so that include directives in the configuration file are processed as if run by a similarly chrooted named.

-v: This option prints the version of the named-checkconf program and exits.

-x: When printing the configuration files in canonical form, this option obscures shared secrets by replacing them with strings of question marks (?). This allows the contents of named.conf and related files to be shared - for example, when submitting bug reports - without compromising private data. This option cannot be used without -p.

-z: This option performs a test load of all zones of type primary found in named.conf.

filename: This indicates the name of the configuration file to be checked. If not specified, it defaults to /usr/local/etc/named.conf.

Return Values

named-checkconf returns an exit status of 1 if errors were detected and 0 otherwise.

named-checkzone - zone file validation tool

Synopsis

named-checkzone [-d] [-h] [-j] [-q] [-v] [-c class] [-C mode] [-f format] [-F format] [-J filename] [-i mode] [-k mode] [-m mode] [-M mode] [-n mode] [-l ttl] [-L serial] [-o filename] [-r mode] [-s style] [-S mode] [-t directory] [-T mode] [-w directory] [-D] [-W mode] {zonename} {filename}

Description

named-checkzone checks the syntax and integrity of a zone file. It performs the same checks as named does when loading a zone. This makes named-checkzone useful for checking zone files before configuring them into a name server.

Options

-d: This option enables debugging.

-h: This option prints the usage summary and exits.

-q: This option sets quiet mode, which only sets an exit code to indicate successful or failed completion.

-v: This option prints the version of the named-checkzone program and exits.

-j: When loading a zone file, this option tells named to read the journal if it exists. The journal file name is assumed to be the zone file name with the string .jnl appended.

-J filename: When loading the zone file, this option tells named to read the journal from the given file, if it exists. This implies -j.

-c class: This option specifies the class of the zone. If not specified, IN is assumed.

-C mode

This option controls check mode on zone files when loading. Possible modes are check-svcb:fail and check-svcb:ignore.

check-svcb:fail turns on additional checks on _dns SVCB records and check-svcb:ignore disables these checks. The default is check-svcb:fail.

-i mode

This option performs post-load zone integrity checks. Possible modes are full (the default), full-sibling, local, local-sibling, and none.

Mode full checks that MX records refer to A or AAAA records (both in-zone and out-of-zone hostnames). Mode local only checks MX records which refer to in-zone hostnames.

Mode full checks that SRV records refer to A or AAAA records (both in-zone and out-of-zone hostnames). Mode local only checks SRV records which refer to in-zone hostnames.

Mode full checks that delegation NS records refer to A or AAAA records (both in-zone and out-of-zone hostnames). It also checks that glue address records in the zone match those advertised by the child. Mode local only checks NS records which refer to in-zone hostnames or verifies that some required glue exists, i.e., when the name server is in a child zone.

Modes full-sibling and local-sibling disable sibling glue checks, but are otherwise the same as full and local, respectively.

Mode none disables the checks.

-f format: This option specifies the format of the zone file. Possible formats are text (the default), and raw.

-F format

This option specifies the format of the output file specified. For named-checkzone, this does not have any effect unless it dumps the zone contents.

Possible formats are text (the default), which is the standard textual representation of the zone, and raw and raw=N, which store the zone in a binary format for rapid loading by named. raw=N specifies the format version of the raw zone file: if N is 0, the raw file can be read by any version of named; if N is 1, the file can only be read by release 9.9.0 or higher. The default is 1.

-k mode: This option performs check-names checks with the specified failure mode. Possible modes are fail, warn (the default), and ignore.

-l ttl: This option sets a maximum permissible TTL for the input file. Any record with a TTL higher than this value causes the zone to be rejected. This is similar to using the max-zone-ttl option in named.conf.

-L serial: When compiling a zone to raw format, this option sets the “source serial” value in the header to the specified serial number. This is expected to be used primarily for testing purposes.

-m mode: This option specifies whether MX records should be checked to see if they are addresses. Possible modes are fail, warn (the default), and ignore.

-M mode: This option checks whether a MX record refers to a CNAME. Possible modes are fail, warn (the default), and ignore.

-n mode: This option specifies whether NS records should be checked to see if they are addresses. Possible modes are fail, warn (the default), and ignore.

-o filename: This option writes the zone output to filename. If filename is -, then the zone output is written to standard output.

-r mode: This option checks for records that are treated as different by DNSSEC but are semantically equal in plain DNS. Possible modes are fail, warn (the default), and ignore.

-s style: This option specifies the style of the dumped zone file. Possible styles are full (the default) and relative. The full format is most suitable for processing automatically by a separate script. The relative format is more human-readable and is thus suitable for editing by hand. This does not have any effect unless it dumps the zone contents. It also does not have any meaning if the output format is not text.

-S mode: This option checks whether an SRV record refers to a CNAME. Possible modes are fail, warn (the default), and ignore.

-t directory: This option tells named to chroot to directory, so that include directives in the configuration file are processed as if run by a similarly chrooted named.

-T mode: This option checks whether Sender Policy Framework (SPF) records exist and issues a warning if an SPF-formatted TXT record is not also present. Possible modes are warn (the default) and ignore.

-w directory: This option instructs named to chdir to directory, so that relative filenames in master file $INCLUDE directives work. This is similar to the directory clause in named.conf.

-D: This option dumps the zone file in canonical format.

-W mode: This option specifies whether to check for non-terminal wildcards. Non-terminal wildcards are almost always the result of a failure to understand the wildcard matching algorithm (RFC 4592). Possible modes are warn (the default) and ignore.

zonename: This indicates the domain name of the zone being checked.

filename: This is the name of the zone file.

Return Values

named-checkzone returns an exit status of 1 if errors were detected and 0 otherwise.

named-compilezone - zone file converting tool

Synopsis

named-compilezone [-d] [-h] [-j] [-q] [-v] [-c class] [-C mode] [-f format] [-F format] [-J filename] [-i mode] [-k mode] [-m mode] [-M mode] [-n mode] [-l ttl] [-L serial] [-r mode] [-s style] [-S mode] [-t directory] [-T mode] [-w directory] [-D] [-W mode] {-o filename} {zonename} {filename}

Description

named-compilezone checks the syntax and integrity of a zone file, and dumps the zone contents to a specified file in a specified format. It applies strict check levels by default, since the dump output is used as an actual zone file loaded by named. When manually specified otherwise, the check levels must at least be as strict as those specified in the named configuration file.

Options

-d: This option enables debugging.

-h: This option prints the usage summary and exits.

-q: This option sets quiet mode, which only sets an exit code to indicate successful or failed completion.

-v: This option prints the version of the named-checkzone program and exits.

-j: When loading a zone file, this option tells named to read the journal if it exists. The journal file name is assumed to be the zone file name with the string .jnl appended.

-J filename: When loading the zone file, this option tells named to read the journal from the given file, if it exists. This implies -j.

-c class: This option specifies the class of the zone. If not specified, IN is assumed.

-C mode

This option controls check mode on zone files when loading. Possible modes are check-svcb:fail and check-svcb:ignore.

check-svcb:fail turns on additional checks on _dns SVCB records and check-svcb:ignore disables these checks. The default is check-svcb:fail.

-i mode

This option performs post-load zone integrity checks. Possible modes are full (the default), full-sibling, local, local-sibling, and none.

Mode full checks that MX records refer to A or AAAA records (both in-zone and out-of-zone hostnames). Mode local only checks MX records which refer to in-zone hostnames.

Mode full checks that SRV records refer to A or AAAA records (both in-zone and out-of-zone hostnames). Mode local only checks SRV records which refer to in-zone hostnames.

Mode full checks that delegation NS records refer to A or AAAA records (both in-zone and out-of-zone hostnames). It also checks that glue address records in the zone match those advertised by the child. Mode local only checks NS records which refer to in-zone hostnames or verifies that some required glue exists, i.e., when the name server is in a child zone.

Modes full-sibling and local-sibling disable sibling glue checks, but are otherwise the same as full and local, respectively.

Mode none disables the checks.

-f format: This option specifies the format of the zone file. Possible formats are text (the default), and raw.

-F format

This option specifies the format of the output file specified. For named-checkzone, this does not have any effect unless it dumps the zone contents.

Possible formats are text (the default), which is the standard textual representation of the zone, and raw and raw=N, which store the zone in a binary format for rapid loading by named. raw=N specifies the format version of the raw zone file: if N is 0, the raw file can be read by any version of named; if N is 1, the file can only be read by release 9.9.0 or higher. The default is 1.

-k mode: This option performs check-names checks with the specified failure mode. Possible modes are fail (the default), warn, and ignore.

-l ttl: This option sets a maximum permissible TTL for the input file. Any record with a TTL higher than this value causes the zone to be rejected. This is similar to using the max-zone-ttl option in named.conf.

-L serial: When compiling a zone to raw format, this option sets the “source serial” value in the header to the specified serial number. This is expected to be used primarily for testing purposes.

-m mode: This option specifies whether MX records should be checked to see if they are addresses. Possible modes are fail, warn (the default), and ignore.

-M mode: This option checks whether a MX record refers to a CNAME. Possible modes are fail, warn (the default), and ignore.

-n mode: This option specifies whether NS records should be checked to see if they are addresses. Possible modes are fail (the default), warn, and ignore.

-o filename: This option writes the zone output to filename. If filename is -, then the zone output is written to standard output. This is mandatory for named-compilezone.

-r mode: This option checks for records that are treated as different by DNSSEC but are semantically equal in plain DNS. Possible modes are fail, warn (the default), and ignore.

-s style: This option specifies the style of the dumped zone file. Possible styles are full (the default) and relative. The full format is most suitable for processing automatically by a separate script. The relative format is more human-readable and is thus suitable for editing by hand.

-S mode: This option checks whether an SRV record refers to a CNAME. Possible modes are fail, warn (the default), and ignore.

-t directory: This option tells named to chroot to directory, so that include directives in the configuration file are processed as if run by a similarly chrooted named.

-T mode: This option checks whether Sender Policy Framework (SPF) records exist and issues a warning if an SPF-formatted TXT record is not also present. Possible modes are warn (the default) and ignore.

-w directory: This option instructs named to chdir to directory, so that relative filenames in master file $INCLUDE directives work. This is similar to the directory clause in named.conf.

-D: This option dumps the zone file in canonical format. This is always enabled for named-compilezone.

-W mode: This option specifies whether to check for non-terminal wildcards. Non-terminal wildcards are almost always the result of a failure to understand the wildcard matching algorithm (RFC 4592). Possible modes are warn (the default) and ignore.

zonename: This indicates the domain name of the zone being checked.

filename: This is the name of the zone file.

Return Values

named-compilezone returns an exit status of 1 if errors were detected and 0 otherwise.

named-journalprint - print zone journal in human-readable form

Synopsis

named-journalprint [-c serial] [-dux] {journal}

Description

named-journalprint scans the contents of a zone journal file, printing it in a human-readable form, or, optionally, converting it to a different journal file format.

Journal files are automatically created by named when changes are made to dynamic zones (e.g., by nsupdate). They record each addition or deletion of a resource record, in binary format, allowing the changes to be re-applied to the zone when the server is restarted after a shutdown or crash. By default, the name of the journal file is formed by appending the extension .jnl to the name of the corresponding zone file.

named-journalprint converts the contents of a given journal file into a human-readable text format. Each line begins with add or del, to indicate whether the record was added or deleted, and continues with the resource record in master-file format.

The -c (compact) option provides a mechanism to reduce the size of a journal by removing (most/all) transactions prior to the specified serial number. Note: this option must not be used while named is running, and can cause data loss if the zone file has not been updated to contain the data being removed from the journal. Use with extreme caution.

The -x option causes additional data about the journal file to be printed at the beginning of the output and before each group of changes.

The -u (upgrade) and -d (downgrade) options recreate the journal file with a modified format version. The existing journal file is replaced. -d writes out the journal in the format used by versions of BIND up to 9.16.11; -u writes it out in the format used by versions since 9.16.13. (9.16.12 is omitted due to a journal-formatting bug in that release.) Note that these options must not be used while named is running.

named-nzd2nzf - convert an NZD database to NZF text format

Synopsis

named-nzd2nzf {filename}

Description

named-nzd2nzf converts an NZD database to NZF format and prints it to standard output. This can be used to review the configuration of zones that were added to named via rndc addzone. It can also be used to restore the old file format when rolling back from a newer version of BIND to an older version.

Arguments

filename: This is the name of the .nzd file whose contents should be printed.

named-rrchecker - syntax checker for individual DNS resource records

Synopsis

named-rrchecker [-h] [-o origin] [-p] [-u] [-C] [-T] [-P]

Description

named-rrchecker reads a individual DNS resource record from standard input and checks whether it is syntactically correct.

Options

-h: This option prints out the help menu.

-o origin: This option specifies the origin to be used when interpreting the record.

-p: This option prints out the resulting record in canonical form. If there is no canonical form defined, the record is printed in unknown record format.

-u: This option prints out the resulting record in unknown record form.

-C, -T, -P: These options print out the known class, standard type, and private type mnemonics, respectively.

named.conf - configuration file for named

Synopsis

named.conf

Description

named.conf is the configuration file for named.

For complete documentation about the configuration statements, please refer to the Configuration Reference section in the BIND 9 Administrator Reference Manual.

Statements are enclosed in braces and terminated with a semi-colon. Clauses in the statements are also semi-colon terminated. The usual comment styles are supported:

C style: /* */

C++ style: // to end of line

Unix style: # to end of line

acl <string> { <address_match_element>; ... }; // may occur multiple times

controls {
	inet ( <ipv4_address> | <ipv6_address> | * ) [ port ( <integer> | * ) ] allow { <address_match_element>; ... } [ keys { <string>; ... } ] [ read-only <boolean> ]; // may occur multiple times
	unix <quoted_string> perm <integer> owner <integer> group <integer> [ keys { <string>; ... } ] [ read-only <boolean> ]; // may occur multiple times
}; // may occur multiple times

dlz <string> {
	database <string>;
	search <boolean>;
}; // may occur multiple times

dnssec-policy <string> {
	cdnskey <boolean>;
	cds-digest-types { <string>; ... };
	dnskey-ttl <duration>;
	inline-signing <boolean>;
	keys { ( csk | ksk | zsk ) [ ( key-directory ) ] lifetime <duration_or_unlimited> algorithm <string> [ <integer> ]; ... };
	max-zone-ttl <duration>;
	nsec3param [ iterations <integer> ] [ optout <boolean> ] [ salt-length <integer> ];
	parent-ds-ttl <duration>;
	parent-propagation-delay <duration>;
	publish-safety <duration>;
	purge-keys <duration>;
	retire-safety <duration>;
	signatures-refresh <duration>;
	signatures-validity <duration>;
	signatures-validity-dnskey <duration>;
	zone-propagation-delay <duration>;
}; // may occur multiple times

dyndb <string> <quoted_string> { <unspecified-text> }; // may occur multiple times

http <string> {
	endpoints { <quoted_string>; ... };
	listener-clients <integer>;
	streams-per-connection <integer>;
}; // may occur multiple times

key <string> {
	algorithm <string>;
	secret <string>;
}; // may occur multiple times

logging {
	category <string> { <string>; ... }; // may occur multiple times
	channel <string> {
		buffered <boolean>;
		file <quoted_string> [ versions ( unlimited | <integer> ) ] [ size <size> ] [ suffix ( increment | timestamp ) ];
		null;
		print-category <boolean>;
		print-severity <boolean>;
		print-time ( iso8601 | iso8601-utc | local | <boolean> );
		severity <log_severity>;
		stderr;
		syslog [ <syslog_facility> ];
	}; // may occur multiple times
};

managed-keys { <string> ( static-key | initial-key | static-ds | initial-ds ) <integer> <integer> <integer> <quoted_string>; ... }; // may occur multiple times, deprecated

options {
	allow-new-zones <boolean>;
	allow-notify { <address_match_element>; ... };
	allow-proxy { <address_match_element>; ... }; // experimental
	allow-proxy-on { <address_match_element>; ... }; // experimental
	allow-query { <address_match_element>; ... };
	allow-query-cache { <address_match_element>; ... };
	allow-query-cache-on { <address_match_element>; ... };
	allow-query-on { <address_match_element>; ... };
	allow-recursion { <address_match_element>; ... };
	allow-recursion-on { <address_match_element>; ... };
	allow-transfer [ port <integer> ] [ transport <string> ] { <address_match_element>; ... };
	allow-update { <address_match_element>; ... };
	allow-update-forwarding { <address_match_element>; ... };
	also-notify [ port <integer> ] [ source ( <ipv4_address> | * ) ] [ source-v6 ( <ipv6_address> | * ) ] { ( <remote-servers> | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ) [ key <string> ] [ tls <string> ]; ... };
	answer-cookie <boolean>;
	attach-cache <string>;
	auth-nxdomain <boolean>;
	automatic-interface-scan <boolean>;
	avoid-v4-udp-ports { <portrange>; ... }; // deprecated
	avoid-v6-udp-ports { <portrange>; ... }; // deprecated
	bindkeys-file <quoted_string>; // test only
	blackhole { <address_match_element>; ... };
	catalog-zones { zone <string> [ default-primaries [ port <integer> ] [ source ( <ipv4_address> | * ) ] [ source-v6 ( <ipv6_address> | * ) ] { ( <remote-servers> | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ) [ key <string> ] [ tls <string> ]; ... } ] [ zone-directory <quoted_string> ] [ in-memory <boolean> ] [ min-update-interval <duration> ]; ... };
	check-dup-records ( fail | warn | ignore );
	check-integrity <boolean>;
	check-mx ( fail | warn | ignore );
	check-mx-cname ( fail | warn | ignore );
	check-names ( primary | master | secondary | slave | response ) ( fail | warn | ignore ); // may occur multiple times
	check-sibling <boolean>;
	check-spf ( warn | ignore );
	check-srv-cname ( fail | warn | ignore );
	check-svcb <boolean>;
	check-wildcard <boolean>;
	clients-per-query <integer>;
	cookie-algorithm ( siphash24 );
	cookie-secret <string>; // may occur multiple times
	deny-answer-addresses { <address_match_element>; ... } [ except-from { <string>; ... } ];
	deny-answer-aliases { <string>; ... } [ except-from { <string>; ... } ];
	dialup ( notify | notify-passive | passive | refresh | <boolean> ); // deprecated
	directory <quoted_string>;
	disable-algorithms <string> { <string>; ... }; // may occur multiple times
	disable-ds-digests <string> { <string>; ... }; // may occur multiple times
	disable-empty-zone <string>; // may occur multiple times
	dns64 <netprefix> {
		break-dnssec <boolean>;
		clients { <address_match_element>; ... };
		exclude { <address_match_element>; ... };
		mapped { <address_match_element>; ... };
		recursive-only <boolean>;
		suffix <ipv6_address>;
	}; // may occur multiple times
	dns64-contact <string>;
	dns64-server <string>;
	dnskey-sig-validity <integer>; // obsolete
	dnsrps-enable <boolean>; // not configured
	dnsrps-library <quoted_string>; // not configured
	dnsrps-options { <unspecified-text> }; // not configured
	dnssec-accept-expired <boolean>;
	dnssec-dnskey-kskonly <boolean>; // obsolete
	dnssec-loadkeys-interval <integer>;
	dnssec-must-be-secure <string> <boolean>; // may occur multiple times, deprecated
	dnssec-policy <string>;
	dnssec-secure-to-insecure <boolean>; // obsolete
	dnssec-update-mode ( maintain | no-resign ); // obsolete
	dnssec-validation ( yes | no | auto );
	dnstap { ( all | auth | client | forwarder | resolver | update ) [ ( query | response ) ]; ... }; // not configured
	dnstap-identity ( <quoted_string> | none | hostname ); // not configured
	dnstap-output ( file | unix ) <quoted_string> [ size ( unlimited | <size> ) ] [ versions ( unlimited | <integer> ) ] [ suffix ( increment | timestamp ) ]; // not configured
	dnstap-version ( <quoted_string> | none ); // not configured
	dual-stack-servers [ port <integer> ] { ( <quoted_string> [ port <integer> ] | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ); ... };
	dump-file <quoted_string>;
	edns-udp-size <integer>;
	empty-contact <string>;
	empty-server <string>;
	empty-zones-enable <boolean>;
	fetch-quota-params <integer> <fixedpoint> <fixedpoint> <fixedpoint>;
	fetches-per-server <integer> [ ( drop | fail ) ];
	fetches-per-zone <integer> [ ( drop | fail ) ];
	flush-zones-on-shutdown <boolean>;
	forward ( first | only );
	forwarders [ port <integer> ] [ tls <string> ] { ( <ipv4_address> | <ipv6_address> ) [ port <integer> ] [ tls <string> ]; ... };
	fstrm-set-buffer-hint <integer>; // not configured
	fstrm-set-flush-timeout <integer>; // not configured
	fstrm-set-input-queue-size <integer>; // not configured
	fstrm-set-output-notify-threshold <integer>; // not configured
	fstrm-set-output-queue-model ( mpsc | spsc ); // not configured
	fstrm-set-output-queue-size <integer>; // not configured
	fstrm-set-reopen-interval <duration>; // not configured
	geoip-directory ( <quoted_string> | none );
	heartbeat-interval <integer>; // deprecated
	hostname ( <quoted_string> | none );
	http-listener-clients <integer>;
	http-port <integer>;
	http-streams-per-connection <integer>;
	https-port <integer>;
	interface-interval <duration>;
	ipv4only-contact <string>;
	ipv4only-enable <boolean>;
	ipv4only-server <string>;
	ixfr-from-differences ( primary | master | secondary | slave | <boolean> );
	keep-response-order { <address_match_element>; ... }; // obsolete
	key-directory <quoted_string>;
	lame-ttl <duration>;
	listen-on [ port <integer> ] [ proxy <string> ] [ tls <string> ] [ http <string> ] { <address_match_element>; ... }; // may occur multiple times
	listen-on-v6 [ port <integer> ] [ proxy <string> ] [ tls <string> ] [ http <string> ] { <address_match_element>; ... }; // may occur multiple times
	lmdb-mapsize <sizeval>;
	managed-keys-directory <quoted_string>;
	masterfile-format ( raw | text );
	masterfile-style ( full | relative );
	match-mapped-addresses <boolean>;
	max-cache-size ( default | unlimited | <sizeval> | <percentage> );
	max-cache-ttl <duration>;
	max-clients-per-query <integer>;
	max-ixfr-ratio ( unlimited | <percentage> );
	max-journal-size ( default | unlimited | <sizeval> );
	max-ncache-ttl <duration>;
	max-records <integer>;
	max-recursion-depth <integer>;
	max-recursion-queries <integer>;
	max-refresh-time <integer>;
	max-retry-time <integer>;
	max-rsa-exponent-size <integer>;
	max-stale-ttl <duration>;
	max-transfer-idle-in <integer>;
	max-transfer-idle-out <integer>;
	max-transfer-time-in <integer>;
	max-transfer-time-out <integer>;
	max-udp-size <integer>;
	max-zone-ttl ( unlimited | <duration> ); // deprecated
	memstatistics <boolean>;
	memstatistics-file <quoted_string>;
	message-compression <boolean>;
	min-cache-ttl <duration>;
	min-ncache-ttl <duration>;
	min-refresh-time <integer>;
	min-retry-time <integer>;
	minimal-any <boolean>;
	minimal-responses ( no-auth | no-auth-recursive | <boolean> );
	multi-master <boolean>;
	new-zones-directory <quoted_string>;
	no-case-compress { <address_match_element>; ... };
	nocookie-udp-size <integer>;
	notify ( explicit | master-only | primary-only | <boolean> );
	notify-delay <integer>;
	notify-rate <integer>;
	notify-source ( <ipv4_address> | * );
	notify-source-v6 ( <ipv6_address> | * );
	notify-to-soa <boolean>;
	nsec3-test-zone <boolean>; // test only
	nta-lifetime <duration>;
	nta-recheck <duration>;
	nxdomain-redirect <string>;
	parental-source ( <ipv4_address> | * );
	parental-source-v6 ( <ipv6_address> | * );
	pid-file ( <quoted_string> | none );
	port <integer>;
	preferred-glue <string>;
	prefetch <integer> [ <integer> ];
	provide-ixfr <boolean>;
	qname-minimization ( strict | relaxed | disabled | off );
	query-source [ address ] ( <ipv4_address> | * );
	query-source-v6 [ address ] ( <ipv6_address> | * );
	querylog <boolean>;
	rate-limit {
		all-per-second <integer>;
		errors-per-second <integer>;
		exempt-clients { <address_match_element>; ... };
		ipv4-prefix-length <integer>;
		ipv6-prefix-length <integer>;
		log-only <boolean>;
		max-table-size <integer>;
		min-table-size <integer>;
		nodata-per-second <integer>;
		nxdomains-per-second <integer>;
		qps-scale <integer>;
		referrals-per-second <integer>;
		responses-per-second <integer>;
		slip <integer>;
		window <integer>;
	};
	recursing-file <quoted_string>;
	recursion <boolean>;
	recursive-clients <integer>;
	request-expire <boolean>;
	request-ixfr <boolean>;
	request-nsid <boolean>;
	require-server-cookie <boolean>;
	resolver-query-timeout <integer>;
	resolver-use-dns64 <boolean>;
	response-padding { <address_match_element>; ... } block-size <integer>;
	response-policy { zone <string> [ add-soa <boolean> ] [ log <boolean> ] [ max-policy-ttl <duration> ] [ min-update-interval <duration> ] [ policy ( cname | disabled | drop | given | no-op | nodata | nxdomain | passthru | tcp-only <quoted_string> ) ] [ recursive-only <boolean> ] [ nsip-enable <boolean> ] [ nsdname-enable <boolean> ] [ ede <string> ]; ... } [ add-soa <boolean> ] [ break-dnssec <boolean> ] [ max-policy-ttl <duration> ] [ min-update-interval <duration> ] [ min-ns-dots <integer> ] [ nsip-wait-recurse <boolean> ] [ nsdname-wait-recurse <boolean> ] [ qname-wait-recurse <boolean> ] [ recursive-only <boolean> ] [ nsip-enable <boolean> ] [ nsdname-enable <boolean> ] [ dnsrps-enable <boolean> ] [ dnsrps-options { <unspecified-text> } ];
	reuseport <boolean>;
	root-key-sentinel <boolean>;
	rrset-order { [ class <string> ] [ type <string> ] [ name <quoted_string> ] <string> <string>; ... };
	secroots-file <quoted_string>;
	send-cookie <boolean>;
	serial-query-rate <integer>;
	serial-update-method ( date | increment | unixtime );
	server-id ( <quoted_string> | none | hostname );
	servfail-ttl <duration>;
	session-keyalg <string>;
	session-keyfile ( <quoted_string> | none );
	session-keyname <string>;
	sig-signing-nodes <integer>;
	sig-signing-signatures <integer>;
	sig-signing-type <integer>;
	sig-validity-interval <integer> [ <integer> ]; // obsolete
	sortlist { <address_match_element>; ... };
	stale-answer-client-timeout ( disabled | off | <integer> );
	stale-answer-enable <boolean>;
	stale-answer-ttl <duration>;
	stale-cache-enable <boolean>;
	stale-refresh-time <duration>;
	startup-notify-rate <integer>;
	statistics-file <quoted_string>;
	synth-from-dnssec <boolean>;
	tcp-advertised-timeout <integer>;
	tcp-clients <integer>;
	tcp-idle-timeout <integer>;
	tcp-initial-timeout <integer>;
	tcp-keepalive-timeout <integer>;
	tcp-listen-queue <integer>;
	tcp-receive-buffer <integer>;
	tcp-send-buffer <integer>;
	tkey-domain <quoted_string>;
	tkey-gssapi-credential <quoted_string>;
	tkey-gssapi-keytab <quoted_string>;
	tls-port <integer>;
	transfer-format ( many-answers | one-answer );
	transfer-message-size <integer>;
	transfer-source ( <ipv4_address> | * );
	transfer-source-v6 ( <ipv6_address> | * );
	transfers-in <integer>;
	transfers-out <integer>;
	transfers-per-ns <integer>;
	trust-anchor-telemetry <boolean>; // experimental
	try-tcp-refresh <boolean>;
	udp-receive-buffer <integer>;
	udp-send-buffer <integer>;
	update-check-ksk <boolean>; // obsolete
	update-quota <integer>;
	use-v4-udp-ports { <portrange>; ... }; // deprecated
	use-v6-udp-ports { <portrange>; ... }; // deprecated
	v6-bias <integer>;
	validate-except { <string>; ... };
	version ( <quoted_string> | none );
	zero-no-soa-ttl <boolean>;
	zero-no-soa-ttl-cache <boolean>;
	zone-statistics ( full | terse | none | <boolean> );
};

parental-agents <string> [ port <integer> ] [ source ( <ipv4_address> | * ) ] [ source-v6 ( <ipv6_address> | * ) ] { ( <remote-servers> | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ) [ key <string> ] [ tls <string> ]; ... }; // may occur multiple times

plugin ( query ) <string> [ { <unspecified-text> } ]; // may occur multiple times

primaries <string> [ port <integer> ] [ source ( <ipv4_address> | * ) ] [ source-v6 ( <ipv6_address> | * ) ] { ( <remote-servers> | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ) [ key <string> ] [ tls <string> ]; ... }; // may occur multiple times

server <netprefix> {
	bogus <boolean>;
	edns <boolean>;
	edns-udp-size <integer>;
	edns-version <integer>;
	keys <server_key>;
	max-udp-size <integer>;
	notify-source ( <ipv4_address> | * );
	notify-source-v6 ( <ipv6_address> | * );
	padding <integer>;
	provide-ixfr <boolean>;
	query-source [ address ] ( <ipv4_address> | * );
	query-source-v6 [ address ] ( <ipv6_address> | * );
	request-expire <boolean>;
	request-ixfr <boolean>;
	request-nsid <boolean>;
	require-cookie <boolean>;
	send-cookie <boolean>;
	tcp-keepalive <boolean>;
	tcp-only <boolean>;
	transfer-format ( many-answers | one-answer );
	transfer-source ( <ipv4_address> | * );
	transfer-source-v6 ( <ipv6_address> | * );
	transfers <integer>;
}; // may occur multiple times

statistics-channels {
	inet ( <ipv4_address> | <ipv6_address> | * ) [ port ( <integer> | * ) ] [ allow { <address_match_element>; ... } ]; // may occur multiple times
}; // may occur multiple times

tls <string> {
	ca-file <quoted_string>;
	cert-file <quoted_string>;
	ciphers <string>;
	dhparam-file <quoted_string>;
	key-file <quoted_string>;
	prefer-server-ciphers <boolean>;
	protocols { <string>; ... };
	remote-hostname <quoted_string>;
	session-tickets <boolean>;
}; // may occur multiple times

trust-anchors { <string> ( static-key | initial-key | static-ds | initial-ds ) <integer> <integer> <integer> <quoted_string>; ... }; // may occur multiple times

trusted-keys { <string> <integer> <integer> <integer> <quoted_string>; ... }; // may occur multiple times, deprecated

view <string> [ <class> ] {
	allow-new-zones <boolean>;
	allow-notify { <address_match_element>; ... };
	allow-proxy { <address_match_element>; ... }; // experimental
	allow-proxy-on { <address_match_element>; ... }; // experimental
	allow-query { <address_match_element>; ... };
	allow-query-cache { <address_match_element>; ... };
	allow-query-cache-on { <address_match_element>; ... };
	allow-query-on { <address_match_element>; ... };
	allow-recursion { <address_match_element>; ... };
	allow-recursion-on { <address_match_element>; ... };
	allow-transfer [ port <integer> ] [ transport <string> ] { <address_match_element>; ... };
	allow-update { <address_match_element>; ... };
	allow-update-forwarding { <address_match_element>; ... };
	also-notify [ port <integer> ] [ source ( <ipv4_address> | * ) ] [ source-v6 ( <ipv6_address> | * ) ] { ( <remote-servers> | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ) [ key <string> ] [ tls <string> ]; ... };
	attach-cache <string>;
	auth-nxdomain <boolean>;
	catalog-zones { zone <string> [ default-primaries [ port <integer> ] [ source ( <ipv4_address> | * ) ] [ source-v6 ( <ipv6_address> | * ) ] { ( <remote-servers> | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ) [ key <string> ] [ tls <string> ]; ... } ] [ zone-directory <quoted_string> ] [ in-memory <boolean> ] [ min-update-interval <duration> ]; ... };
	check-dup-records ( fail | warn | ignore );
	check-integrity <boolean>;
	check-mx ( fail | warn | ignore );
	check-mx-cname ( fail | warn | ignore );
	check-names ( primary | master | secondary | slave | response ) ( fail | warn | ignore ); // may occur multiple times
	check-sibling <boolean>;
	check-spf ( warn | ignore );
	check-srv-cname ( fail | warn | ignore );
	check-svcb <boolean>;
	check-wildcard <boolean>;
	clients-per-query <integer>;
	deny-answer-addresses { <address_match_element>; ... } [ except-from { <string>; ... } ];
	deny-answer-aliases { <string>; ... } [ except-from { <string>; ... } ];
	dialup ( notify | notify-passive | passive | refresh | <boolean> ); // deprecated
	disable-algorithms <string> { <string>; ... }; // may occur multiple times
	disable-ds-digests <string> { <string>; ... }; // may occur multiple times
	disable-empty-zone <string>; // may occur multiple times
	dlz <string> {
		database <string>;
		search <boolean>;
	}; // may occur multiple times
	dns64 <netprefix> {
		break-dnssec <boolean>;
		clients { <address_match_element>; ... };
		exclude { <address_match_element>; ... };
		mapped { <address_match_element>; ... };
		recursive-only <boolean>;
		suffix <ipv6_address>;
	}; // may occur multiple times
	dns64-contact <string>;
	dns64-server <string>;
	dnskey-sig-validity <integer>; // obsolete
	dnsrps-enable <boolean>; // not configured
	dnsrps-options { <unspecified-text> }; // not configured
	dnssec-accept-expired <boolean>;
	dnssec-dnskey-kskonly <boolean>; // obsolete
	dnssec-loadkeys-interval <integer>;
	dnssec-must-be-secure <string> <boolean>; // may occur multiple times, deprecated
	dnssec-policy <string>;
	dnssec-secure-to-insecure <boolean>; // obsolete
	dnssec-update-mode ( maintain | no-resign ); // obsolete
	dnssec-validation ( yes | no | auto );
	dnstap { ( all | auth | client | forwarder | resolver | update ) [ ( query | response ) ]; ... }; // not configured
	dual-stack-servers [ port <integer> ] { ( <quoted_string> [ port <integer> ] | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ); ... };
	dyndb <string> <quoted_string> { <unspecified-text> }; // may occur multiple times
	edns-udp-size <integer>;
	empty-contact <string>;
	empty-server <string>;
	empty-zones-enable <boolean>;
	fetch-quota-params <integer> <fixedpoint> <fixedpoint> <fixedpoint>;
	fetches-per-server <integer> [ ( drop | fail ) ];
	fetches-per-zone <integer> [ ( drop | fail ) ];
	forward ( first | only );
	forwarders [ port <integer> ] [ tls <string> ] { ( <ipv4_address> | <ipv6_address> ) [ port <integer> ] [ tls <string> ]; ... };
	ipv4only-contact <string>;
	ipv4only-enable <boolean>;
	ipv4only-server <string>;
	ixfr-from-differences ( primary | master | secondary | slave | <boolean> );
	key <string> {
		algorithm <string>;
		secret <string>;
	}; // may occur multiple times
	key-directory <quoted_string>;
	lame-ttl <duration>;
	lmdb-mapsize <sizeval>;
	managed-keys { <string> ( static-key | initial-key | static-ds | initial-ds ) <integer> <integer> <integer> <quoted_string>; ... }; // may occur multiple times, deprecated
	masterfile-format ( raw | text );
	masterfile-style ( full | relative );
	match-clients { <address_match_element>; ... };
	match-destinations { <address_match_element>; ... };
	match-recursive-only <boolean>;
	max-cache-size ( default | unlimited | <sizeval> | <percentage> );
	max-cache-ttl <duration>;
	max-clients-per-query <integer>;
	max-ixfr-ratio ( unlimited | <percentage> );
	max-journal-size ( default | unlimited | <sizeval> );
	max-ncache-ttl <duration>;
	max-records <integer>;
	max-recursion-depth <integer>;
	max-recursion-queries <integer>;
	max-refresh-time <integer>;
	max-retry-time <integer>;
	max-stale-ttl <duration>;
	max-transfer-idle-in <integer>;
	max-transfer-idle-out <integer>;
	max-transfer-time-in <integer>;
	max-transfer-time-out <integer>;
	max-udp-size <integer>;
	max-zone-ttl ( unlimited | <duration> ); // deprecated
	message-compression <boolean>;
	min-cache-ttl <duration>;
	min-ncache-ttl <duration>;
	min-refresh-time <integer>;
	min-retry-time <integer>;
	minimal-any <boolean>;
	minimal-responses ( no-auth | no-auth-recursive | <boolean> );
	multi-master <boolean>;
	new-zones-directory <quoted_string>;
	no-case-compress { <address_match_element>; ... };
	nocookie-udp-size <integer>;
	notify ( explicit | master-only | primary-only | <boolean> );
	notify-delay <integer>;
	notify-source ( <ipv4_address> | * );
	notify-source-v6 ( <ipv6_address> | * );
	notify-to-soa <boolean>;
	nsec3-test-zone <boolean>; // test only
	nta-lifetime <duration>;
	nta-recheck <duration>;
	nxdomain-redirect <string>;
	parental-source ( <ipv4_address> | * );
	parental-source-v6 ( <ipv6_address> | * );
	plugin ( query ) <string> [ { <unspecified-text> } ]; // may occur multiple times
	preferred-glue <string>;
	prefetch <integer> [ <integer> ];
	provide-ixfr <boolean>;
	qname-minimization ( strict | relaxed | disabled | off );
	query-source [ address ] ( <ipv4_address> | * );
	query-source-v6 [ address ] ( <ipv6_address> | * );
	rate-limit {
		all-per-second <integer>;
		errors-per-second <integer>;
		exempt-clients { <address_match_element>; ... };
		ipv4-prefix-length <integer>;
		ipv6-prefix-length <integer>;
		log-only <boolean>;
		max-table-size <integer>;
		min-table-size <integer>;
		nodata-per-second <integer>;
		nxdomains-per-second <integer>;
		qps-scale <integer>;
		referrals-per-second <integer>;
		responses-per-second <integer>;
		slip <integer>;
		window <integer>;
	};
	recursion <boolean>;
	request-expire <boolean>;
	request-ixfr <boolean>;
	request-nsid <boolean>;
	require-server-cookie <boolean>;
	resolver-query-timeout <integer>;
	resolver-use-dns64 <boolean>;
	response-padding { <address_match_element>; ... } block-size <integer>;
	response-policy { zone <string> [ add-soa <boolean> ] [ log <boolean> ] [ max-policy-ttl <duration> ] [ min-update-interval <duration> ] [ policy ( cname | disabled | drop | given | no-op | nodata | nxdomain | passthru | tcp-only <quoted_string> ) ] [ recursive-only <boolean> ] [ nsip-enable <boolean> ] [ nsdname-enable <boolean> ] [ ede <string> ]; ... } [ add-soa <boolean> ] [ break-dnssec <boolean> ] [ max-policy-ttl <duration> ] [ min-update-interval <duration> ] [ min-ns-dots <integer> ] [ nsip-wait-recurse <boolean> ] [ nsdname-wait-recurse <boolean> ] [ qname-wait-recurse <boolean> ] [ recursive-only <boolean> ] [ nsip-enable <boolean> ] [ nsdname-enable <boolean> ] [ dnsrps-enable <boolean> ] [ dnsrps-options { <unspecified-text> } ];
	root-key-sentinel <boolean>;
	rrset-order { [ class <string> ] [ type <string> ] [ name <quoted_string> ] <string> <string>; ... };
	send-cookie <boolean>;
	serial-update-method ( date | increment | unixtime );
	server <netprefix> {
		bogus <boolean>;
		edns <boolean>;
		edns-udp-size <integer>;
		edns-version <integer>;
		keys <server_key>;
		max-udp-size <integer>;
		notify-source ( <ipv4_address> | * );
		notify-source-v6 ( <ipv6_address> | * );
		padding <integer>;
		provide-ixfr <boolean>;
		query-source [ address ] ( <ipv4_address> | * );
		query-source-v6 [ address ] ( <ipv6_address> | * );
		request-expire <boolean>;
		request-ixfr <boolean>;
		request-nsid <boolean>;
		require-cookie <boolean>;
		send-cookie <boolean>;
		tcp-keepalive <boolean>;
		tcp-only <boolean>;
		transfer-format ( many-answers | one-answer );
		transfer-source ( <ipv4_address> | * );
		transfer-source-v6 ( <ipv6_address> | * );
		transfers <integer>;
	}; // may occur multiple times
	servfail-ttl <duration>;
	sig-signing-nodes <integer>;
	sig-signing-signatures <integer>;
	sig-signing-type <integer>;
	sig-validity-interval <integer> [ <integer> ]; // obsolete
	sortlist { <address_match_element>; ... };
	stale-answer-client-timeout ( disabled | off | <integer> );
	stale-answer-enable <boolean>;
	stale-answer-ttl <duration>;
	stale-cache-enable <boolean>;
	stale-refresh-time <duration>;
	synth-from-dnssec <boolean>;
	transfer-format ( many-answers | one-answer );
	transfer-source ( <ipv4_address> | * );
	transfer-source-v6 ( <ipv6_address> | * );
	trust-anchor-telemetry <boolean>; // experimental
	trust-anchors { <string> ( static-key | initial-key | static-ds | initial-ds ) <integer> <integer> <integer> <quoted_string>; ... }; // may occur multiple times
	trusted-keys { <string> <integer> <integer> <integer> <quoted_string>; ... }; // may occur multiple times, deprecated
	try-tcp-refresh <boolean>;
	update-check-ksk <boolean>; // obsolete
	v6-bias <integer>;
	validate-except { <string>; ... };
	zero-no-soa-ttl <boolean>;
	zero-no-soa-ttl-cache <boolean>;
	zone-statistics ( full | terse | none | <boolean> );
}; // may occur multiple times

Any of these zone statements can also be set inside the view statement.

zone <string> [ <class> ] {
	type primary;
	allow-query { <address_match_element>; ... };
	allow-query-on { <address_match_element>; ... };
	allow-transfer [ port <integer> ] [ transport <string> ] { <address_match_element>; ... };
	allow-update { <address_match_element>; ... };
	also-notify [ port <integer> ] [ source ( <ipv4_address> | * ) ] [ source-v6 ( <ipv6_address> | * ) ] { ( <remote-servers> | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ) [ key <string> ] [ tls <string> ]; ... };
	check-dup-records ( fail | warn | ignore );
	check-integrity <boolean>;
	check-mx ( fail | warn | ignore );
	check-mx-cname ( fail | warn | ignore );
	check-names ( fail | warn | ignore );
	check-sibling <boolean>;
	check-spf ( warn | ignore );
	check-srv-cname ( fail | warn | ignore );
	check-svcb <boolean>;
	check-wildcard <boolean>;
	checkds ( explicit | <boolean> );
	database <string>;
	dialup ( notify | notify-passive | passive | refresh | <boolean> ); // deprecated
	dlz <string>;
	dnskey-sig-validity <integer>; // obsolete
	dnssec-dnskey-kskonly <boolean>; // obsolete
	dnssec-loadkeys-interval <integer>;
	dnssec-policy <string>;
	dnssec-secure-to-insecure <boolean>; // obsolete
	dnssec-update-mode ( maintain | no-resign ); // obsolete
	file <quoted_string>;
	forward ( first | only );
	forwarders [ port <integer> ] [ tls <string> ] { ( <ipv4_address> | <ipv6_address> ) [ port <integer> ] [ tls <string> ]; ... };
	inline-signing <boolean>;
	ixfr-from-differences <boolean>;
	journal <quoted_string>;
	key-directory <quoted_string>;
	masterfile-format ( raw | text );
	masterfile-style ( full | relative );
	max-ixfr-ratio ( unlimited | <percentage> );
	max-journal-size ( default | unlimited | <sizeval> );
	max-records <integer>;
	max-transfer-idle-out <integer>;
	max-transfer-time-out <integer>;
	max-zone-ttl ( unlimited | <duration> ); // deprecated
	notify ( explicit | master-only | primary-only | <boolean> );
	notify-delay <integer>;
	notify-source ( <ipv4_address> | * );
	notify-source-v6 ( <ipv6_address> | * );
	notify-to-soa <boolean>;
	nsec3-test-zone <boolean>; // test only
	parental-agents [ port <integer> ] [ source ( <ipv4_address> | * ) ] [ source-v6 ( <ipv6_address> | * ) ] { ( <remote-servers> | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ) [ key <string> ] [ tls <string> ]; ... };
	parental-source ( <ipv4_address> | * );
	parental-source-v6 ( <ipv6_address> | * );
	serial-update-method ( date | increment | unixtime );
	sig-signing-nodes <integer>;
	sig-signing-signatures <integer>;
	sig-signing-type <integer>;
	sig-validity-interval <integer> [ <integer> ]; // obsolete
	update-check-ksk <boolean>; // obsolete
	update-policy ( local | { ( deny | grant ) <string> ( 6to4-self | external | krb5-self | krb5-selfsub | krb5-subdomain | krb5-subdomain-self-rhs | ms-self | ms-selfsub | ms-subdomain | ms-subdomain-self-rhs | name | self | selfsub | selfwild | subdomain | tcp-self | wildcard | zonesub ) [ <string> ] <rrtypelist>; ... } );
	zero-no-soa-ttl <boolean>;
	zone-statistics ( full | terse | none | <boolean> );
};

zone <string> [ <class> ] {
	type secondary;
	allow-notify { <address_match_element>; ... };
	allow-query { <address_match_element>; ... };
	allow-query-on { <address_match_element>; ... };
	allow-transfer [ port <integer> ] [ transport <string> ] { <address_match_element>; ... };
	allow-update-forwarding { <address_match_element>; ... };
	also-notify [ port <integer> ] [ source ( <ipv4_address> | * ) ] [ source-v6 ( <ipv6_address> | * ) ] { ( <remote-servers> | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ) [ key <string> ] [ tls <string> ]; ... };
	check-names ( fail | warn | ignore );
	checkds ( explicit | <boolean> );
	database <string>;
	dialup ( notify | notify-passive | passive | refresh | <boolean> ); // deprecated
	dlz <string>;
	dnskey-sig-validity <integer>; // obsolete
	dnssec-dnskey-kskonly <boolean>; // obsolete
	dnssec-loadkeys-interval <integer>;
	dnssec-policy <string>;
	dnssec-update-mode ( maintain | no-resign ); // obsolete
	file <quoted_string>;
	forward ( first | only );
	forwarders [ port <integer> ] [ tls <string> ] { ( <ipv4_address> | <ipv6_address> ) [ port <integer> ] [ tls <string> ]; ... };
	inline-signing <boolean>;
	ixfr-from-differences <boolean>;
	journal <quoted_string>;
	key-directory <quoted_string>;
	masterfile-format ( raw | text );
	masterfile-style ( full | relative );
	max-ixfr-ratio ( unlimited | <percentage> );
	max-journal-size ( default | unlimited | <sizeval> );
	max-records <integer>;
	max-refresh-time <integer>;
	max-retry-time <integer>;
	max-transfer-idle-in <integer>;
	max-transfer-idle-out <integer>;
	max-transfer-time-in <integer>;
	max-transfer-time-out <integer>;
	min-refresh-time <integer>;
	min-retry-time <integer>;
	multi-master <boolean>;
	notify ( explicit | master-only | primary-only | <boolean> );
	notify-delay <integer>;
	notify-source ( <ipv4_address> | * );
	notify-source-v6 ( <ipv6_address> | * );
	notify-to-soa <boolean>;
	nsec3-test-zone <boolean>; // test only
	parental-agents [ port <integer> ] [ source ( <ipv4_address> | * ) ] [ source-v6 ( <ipv6_address> | * ) ] { ( <remote-servers> | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ) [ key <string> ] [ tls <string> ]; ... };
	parental-source ( <ipv4_address> | * );
	parental-source-v6 ( <ipv6_address> | * );
	primaries [ port <integer> ] [ source ( <ipv4_address> | * ) ] [ source-v6 ( <ipv6_address> | * ) ] { ( <remote-servers> | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ) [ key <string> ] [ tls <string> ]; ... };
	request-expire <boolean>;
	request-ixfr <boolean>;
	sig-signing-nodes <integer>;
	sig-signing-signatures <integer>;
	sig-signing-type <integer>;
	sig-validity-interval <integer> [ <integer> ]; // obsolete
	transfer-source ( <ipv4_address> | * );
	transfer-source-v6 ( <ipv6_address> | * );
	try-tcp-refresh <boolean>;
	update-check-ksk <boolean>; // obsolete
	zero-no-soa-ttl <boolean>;
	zone-statistics ( full | terse | none | <boolean> );
};

zone <string> [ <class> ] {
	type mirror;
	allow-notify { <address_match_element>; ... };
	allow-query { <address_match_element>; ... };
	allow-query-on { <address_match_element>; ... };
	allow-transfer [ port <integer> ] [ transport <string> ] { <address_match_element>; ... };
	allow-update-forwarding { <address_match_element>; ... };
	also-notify [ port <integer> ] [ source ( <ipv4_address> | * ) ] [ source-v6 ( <ipv6_address> | * ) ] { ( <remote-servers> | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ) [ key <string> ] [ tls <string> ]; ... };
	check-names ( fail | warn | ignore );
	database <string>;
	file <quoted_string>;
	ixfr-from-differences <boolean>;
	journal <quoted_string>;
	masterfile-format ( raw | text );
	masterfile-style ( full | relative );
	max-ixfr-ratio ( unlimited | <percentage> );
	max-journal-size ( default | unlimited | <sizeval> );
	max-records <integer>;
	max-refresh-time <integer>;
	max-retry-time <integer>;
	max-transfer-idle-in <integer>;
	max-transfer-idle-out <integer>;
	max-transfer-time-in <integer>;
	max-transfer-time-out <integer>;
	min-refresh-time <integer>;
	min-retry-time <integer>;
	multi-master <boolean>;
	notify ( explicit | master-only | primary-only | <boolean> );
	notify-delay <integer>;
	notify-source ( <ipv4_address> | * );
	notify-source-v6 ( <ipv6_address> | * );
	primaries [ port <integer> ] [ source ( <ipv4_address> | * ) ] [ source-v6 ( <ipv6_address> | * ) ] { ( <remote-servers> | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ) [ key <string> ] [ tls <string> ]; ... };
	request-expire <boolean>;
	request-ixfr <boolean>;
	transfer-source ( <ipv4_address> | * );
	transfer-source-v6 ( <ipv6_address> | * );
	try-tcp-refresh <boolean>;
	zero-no-soa-ttl <boolean>;
	zone-statistics ( full | terse | none | <boolean> );
};

zone <string> [ <class> ] {
	type forward;
	forward ( first | only );
	forwarders [ port <integer> ] [ tls <string> ] { ( <ipv4_address> | <ipv6_address> ) [ port <integer> ] [ tls <string> ]; ... };
};

zone <string> [ <class> ] {
	type hint;
	check-names ( fail | warn | ignore );
	file <quoted_string>;
};

zone <string> [ <class> ] {
	type redirect;
	allow-query { <address_match_element>; ... };
	allow-query-on { <address_match_element>; ... };
	dlz <string>;
	file <quoted_string>;
	masterfile-format ( raw | text );
	masterfile-style ( full | relative );
	max-records <integer>;
	max-zone-ttl ( unlimited | <duration> ); // deprecated
	primaries [ port <integer> ] [ source ( <ipv4_address> | * ) ] [ source-v6 ( <ipv6_address> | * ) ] { ( <remote-servers> | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ) [ key <string> ] [ tls <string> ]; ... };
	zone-statistics ( full | terse | none | <boolean> );
};

zone <string> [ <class> ] {
	type static-stub;
	allow-query { <address_match_element>; ... };
	allow-query-on { <address_match_element>; ... };
	forward ( first | only );
	forwarders [ port <integer> ] [ tls <string> ] { ( <ipv4_address> | <ipv6_address> ) [ port <integer> ] [ tls <string> ]; ... };
	max-records <integer>;
	server-addresses { ( <ipv4_address> | <ipv6_address> ); ... };
	server-names { <string>; ... };
	zone-statistics ( full | terse | none | <boolean> );
};

zone <string> [ <class> ] {
	type stub;
	allow-query { <address_match_element>; ... };
	allow-query-on { <address_match_element>; ... };
	check-names ( fail | warn | ignore );
	database <string>;
	dialup ( notify | notify-passive | passive | refresh | <boolean> ); // deprecated
	file <quoted_string>;
	forward ( first | only );
	forwarders [ port <integer> ] [ tls <string> ] { ( <ipv4_address> | <ipv6_address> ) [ port <integer> ] [ tls <string> ]; ... };
	masterfile-format ( raw | text );
	masterfile-style ( full | relative );
	max-records <integer>;
	max-refresh-time <integer>;
	max-retry-time <integer>;
	max-transfer-idle-in <integer>;
	max-transfer-time-in <integer>;
	min-refresh-time <integer>;
	min-retry-time <integer>;
	multi-master <boolean>;
	primaries [ port <integer> ] [ source ( <ipv4_address> | * ) ] [ source-v6 ( <ipv6_address> | * ) ] { ( <remote-servers> | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ) [ key <string> ] [ tls <string> ]; ... };
	transfer-source ( <ipv4_address> | * );
	transfer-source-v6 ( <ipv6_address> | * );
	zone-statistics ( full | terse | none | <boolean> );
};

zone <string> [ <class> ] {
	in-view <string>;
};

Files

/usr/local/etc/named.conf

named - Internet domain name server

Synopsis

named [ [-4] | [-6] ] [-c config-file] [-C] [-d debug-level] [-D string] [-E engine-name] [-f] [-g] [-L logfile] [-M option] [-m flag] [-n #cpus] [-p port] [-s] [-t directory] [-U #listeners] [-u user] [-v] [-V] ]

Description

named is a Domain Name System (DNS) server, part of the BIND 9 distribution from ISC. For more information on the DNS, see RFC 1033, RFC 1034, and RFC 1035.

When invoked without arguments, named reads the default configuration file /usr/local/etc/named.conf, reads any initial data, and listens for queries.

Options

-4: This option tells named to use only IPv4, even if the host machine is capable of IPv6. -4 and -6 are mutually exclusive.

-6: This option tells named to use only IPv6, even if the host machine is capable of IPv4. -4 and -6 are mutually exclusive.

-c config-file: This option tells named to use config-file as its configuration file instead of the default, /usr/local/etc/named.conf. To ensure that the configuration file can be reloaded after the server has changed its working directory due to to a possible directory option in the configuration file, config-file should be an absolute pathname.

-C

This option prints out the default built-in configuration and exits.

NOTE: This is for debugging purposes only and is not an accurate representation of the actual configuration used by named at runtime.

-d debug-level: This option sets the daemon’s debug level to debug-level. Debugging traces from named become more verbose as the debug level increases.

-D string: This option specifies a string that is used to identify a instance of named in a process listing. The contents of string are not examined.

-E engine-name

When applicable, this option specifies the hardware to use for cryptographic operations, such as a secure key store used for signing.

When BIND 9 is built with OpenSSL, this needs to be set to the OpenSSL engine identifier that drives the cryptographic accelerator or hardware service module (usually pkcs11).

-f: This option runs the server in the foreground (i.e., do not daemonize).

-F: This options turns on FIPS (US Federal Information Processing Standards) mode if the underlying crytographic library supports running in FIPS mode.

-g: This option runs the server in the foreground and forces all logging to stderr.

-L logfile: This option sets the log to the file logfile by default, instead of the system log.

-M option

This option sets the default (comma-separated) memory context options. The possible flags are:

fill: fill blocks of memory with tag values when they are allocated or freed, to assist debugging of memory problems; this is the implicit default if named has been compiled with --enable-developer.
nofill: disable the behavior enabled by fill; this is the implicit default unless named has been compiled with --enable-developer.

-m flag: This option turns on memory usage debugging flags. Possible flags are usage, trace, record, size, and mctx. These correspond to the ISC_MEM_DEBUGXXXX flags described in <isc/mem.h>.

-n #cpus: This option creates #cpus worker threads to take advantage of multiple CPUs. If not specified, named tries to determine the number of CPUs present and creates one thread per CPU. If it is unable to determine the number of CPUs, a single worker thread is created.

-p value: This option specifies the port(s) on which the server will listen for queries. If value is of the form <portnum> or dns=<portnum>, the server will listen for DNS queries on portnum; if not not specified, the default is port 53. If value is of the form tls=<portnum>, the server will listen for TLS queries on portnum; the default is 853. If value is of the form https=<portnum>, the server will listen for HTTPS queries on portnum; the default is 443. If value is of the form http=<portnum>, the server will listen for HTTP queries on portnum; the default is 80.

-s: This option writes memory usage statistics to stdout on exit.

Note

This option is mainly of interest to BIND 9 developers and may be removed or changed in a future release.

-t directory: This option tells named to chroot to directory after processing the command-line arguments, but before reading the configuration file.

Warning

This option should be used in conjunction with the -u option, as chrooting a process running as root doesn’t enhance security on most systems; the way chroot is defined allows a process with root privileges to escape a chroot jail.

-U #listeners: This option tells named the number of #listeners worker threads to listen on, for incoming UDP packets on each address. If not specified, named calculates a default value based on the number of detected CPUs: 1 for 1 CPU, and the number of detected CPUs minus one for machines with more than 1 CPU. This cannot be increased to a value higher than the number of CPUs. If -n has been set to a higher value than the number of detected CPUs, then -U may be increased as high as that value, but no higher.

-u user: This option sets the setuid to user after completing privileged operations, such as creating sockets that listen on privileged ports.

Note

On Linux, named uses the kernel’s capability mechanism to drop all root privileges except the ability to bind to a privileged port and set process resource limits. Unfortunately, this means that the -u option only works when named is run on kernel 2.2.18 or later, or kernel 2.3.99-pre3 or later, since previous kernels did not allow privileges to be retained after setuid.

-v: This option reports the version number and exits.

-V: This option reports the version number, build options, supported cryptographics algorithms, and exits.

-X lock-file: This option has been removed and using it will cause a fatal error.

Signals

In routine operation, signals should not be used to control the nameserver; rndc should be used instead.

SIGHUP: This signal forces a reload of the server.
SIGINT, SIGTERM: These signals shut down the server.

The result of sending any other signals to the server is undefined.

Configuration

The named configuration file is too complex to describe in detail here. A complete description is provided in the BIND 9 Administrator Reference Manual.

named inherits the umask (file creation mode mask) from the parent process. If files created by named, such as journal files, need to have custom permissions, the umask should be set explicitly in the script used to start the named process.

Files

/usr/local/etc/named.conf: The default configuration file.
/usr/local/var/run/named.pid: The default process-id file.

nsec3hash - generate NSEC3 hash

Synopsis

nsec3hash {salt} {algorithm} {iterations} {domain}

nsec3hash -r {algorithm} {flags} {iterations} {salt} {domain}

Description

nsec3hash generates an NSEC3 hash based on a set of NSEC3 parameters. This can be used to check the validity of NSEC3 records in a signed zone.

If this command is invoked as nsec3hash -r, it takes arguments in order, matching the first four fields of an NSEC3 record followed by the domain name: algorithm, flags, iterations, salt, domain. This makes it convenient to copy and paste a portion of an NSEC3 or NSEC3PARAM record into a command line to confirm the correctness of an NSEC3 hash.

Arguments

salt: This is the salt provided to the hash algorithm.

algorithm: This is a number indicating the hash algorithm. Currently the only supported hash algorithm for NSEC3 is SHA-1, which is indicated by the number 1; consequently “1” is the only useful value for this argument.

flags: This is provided for compatibility with NSEC3 record presentation format, but is ignored since the flags do not affect the hash.

iterations: This is the number of additional times the hash should be performed.

domain: This is the domain name to be hashed.

nslookup - query Internet name servers interactively

Synopsis

nslookup [-option] [name | -] [server]

Description

nslookup is a program to query Internet domain name servers. nslookup has two modes: interactive and non-interactive. Interactive mode allows the user to query name servers for information about various hosts and domains or to print a list of hosts in a domain. Non-interactive mode prints just the name and requested information for a host or domain.

Arguments

Interactive mode is entered in the following cases:

when no arguments are given (the default name server is used);
when the first argument is a hyphen (-) and the second argument is the host name or Internet address of a name server.

Non-interactive mode is used when the name or Internet address of the host to be looked up is given as the first argument. The optional second argument specifies the host name or address of a name server.

Options can also be specified on the command line if they precede the arguments and are prefixed with a hyphen. For example, to change the default query type to host information, with an initial timeout of 10 seconds, type:

nslookup -query=hinfo  -timeout=10

The -version option causes nslookup to print the version number and immediately exit.

Interactive Commands

host [server]

This command looks up information for host using the current default server or using server, if specified. If host is an Internet address and the query type is A or PTR, the name of the host is returned. If host is a name and does not have a trailing period (.), the search list is used to qualify the name.

To look up a host not in the current domain, append a period to the name.

server domain | lserver domain

These commands change the default server to domain; lserver uses the initial server to look up information about domain, while server uses the current default server. If an authoritative answer cannot be found, the names of servers that might have the answer are returned.

root

This command is not implemented.

finger

This command is not implemented.

ls

This command is not implemented.

view

This command is not implemented.

help

This command is not implemented.

?

This command is not implemented.

exit

This command exits the program.

set keyword[=value]

This command is used to change state information that affects the lookups. Valid keywords are:

all

This keyword prints the current values of the frequently used options to set. Information about the current default server and host is also printed.

class=value

This keyword changes the query class to one of:

IN: the Internet class
CH: the Chaos class
HS: the Hesiod class
ANY: wildcard

The class specifies the protocol group of the information. The default is IN; the abbreviation for this keyword is cl.

nodebug

This keyword turns on or off the display of the full response packet, and any intermediate response packets, when searching. The default for this keyword is nodebug; the abbreviation for this keyword is [no]deb.

nod2

This keyword turns debugging mode on or off. This displays more about what nslookup is doing. The default is nod2.

domain=name

This keyword sets the search list to name.

nosearch

If the lookup request contains at least one period, but does not end with a trailing period, this keyword appends the domain names in the domain search list to the request until an answer is received. The default is search.

port=value

This keyword changes the default TCP/UDP name server port to value from its default, port 53. The abbreviation for this keyword is po.

querytype=value | type=value

This keyword changes the type of the information query to value. The defaults are A and then AAAA; the abbreviations for these keywords are q and ty.

Please note that it is only possible to specify one query type. Only the default behavior looks up both when an alternative is not specified.

norecurse

This keyword tells the name server to query other servers if it does not have the information. The default is recurse; the abbreviation for this keyword is [no]rec.

ndots=number

This keyword sets the number of dots (label separators) in a domain that disables searching. Absolute names always stop searching.

retry=number

This keyword sets the number of retries to number.

timeout=number

This keyword changes the initial timeout interval to wait for a reply to number, in seconds.

novc

This keyword indicates that a virtual circuit should always be used when sending requests to the server. novc is the default.

nofail

This keyword tries the next nameserver if a nameserver responds with SERVFAIL or a referral (nofail), or terminates the query (fail) on such a response. The default is nofail.

Return Values

nslookup returns with an exit status of 1 if any query failed, and 0 otherwise.

IDN Support

If nslookup has been built with IDN (internationalized domain name) support, it can accept and display non-ASCII domain names. nslookup appropriately converts character encoding of a domain name before sending a request to a DNS server or displaying a reply from the server. To turn off IDN support, define the IDN_DISABLE environment variable. IDN support is disabled if the variable is set when nslookup runs, or when the standard output is not a tty.

Files

/etc/resolv.conf

nsupdate - dynamic DNS update utility

Synopsis

nsupdate [-d] [-D] [-i] [-L level] [ [-g] | [-o] | [-l] | [-y [hmac:]keyname:secret] | [-k keyfile] ] [ [-S] [-K tlskeyfile] [-E tlscertfile] [-A tlscafile] [-H tlshostname] [-O] ] [-t timeout] [-u udptimeout] [-r udpretries] [-v] [-T] [-P] [-V] [ [-4] | [-6] ] [filename]

Description

nsupdate is used to submit Dynamic DNS Update requests, as defined in RFC 2136, to a name server. This allows resource records to be added or removed from a zone without manually editing the zone file. A single update request can contain requests to add or remove more than one resource record.

Zones that are under dynamic control via nsupdate or a DHCP server should not be edited by hand. Manual edits could conflict with dynamic updates and cause data to be lost.

The resource records that are dynamically added or removed with nsupdate must be in the same zone. Requests are sent to the zone’s primary server, which is identified by the MNAME field of the zone’s SOA record.

Transaction signatures can be used to authenticate the Dynamic DNS updates. These use the TSIG resource record type described in RFC 2845, the SIG(0) record described in RFC 2535 and RFC 2931, or GSS-TSIG as described in RFC 3645.

TSIG relies on a shared secret that should only be known to nsupdate and the name server. For instance, suitable key and server statements are added to /usr/local/etc/named.conf so that the name server can associate the appropriate secret key and algorithm with the IP address of the client application that is using TSIG authentication. ddns-confgen can generate suitable configuration fragments. nsupdate uses the -y or -k options to provide the TSIG shared secret; these options are mutually exclusive.

SIG(0) uses public key cryptography. To use a SIG(0) key, the public key must be stored in a KEY record in a zone served by the name server.

GSS-TSIG uses Kerberos credentials. Standard GSS-TSIG mode is switched on with the -g flag. A non-standards-compliant variant of GSS-TSIG used by Windows 2000 can be switched on with the -o flag.

Options

-4: This option sets use of IPv4 only.

-6: This option sets use of IPv6 only.

-A tlscafile: This option specifies the file of the certificate authorities (CA) certificates (in PEM format) in order to verify the remote server TLS certificate when using DNS-over-TLS (DoT), to achieve Strict or Mutual TLS. When used, it will override the certificates from the global certificates store, which are otherwise used by default when -S is enabled. This option can not be used in conjuction with -O, and it implies -S.

-C: Overrides the default resolv.conf file. This is only intended for testing.

-d: This option sets debug mode, which provides tracing information about the update requests that are made and the replies received from the name server.

-D: This option sets extra debug mode.

-E tlscertfile: This option sets the certificate(s) file for authentication for the DNS-over-TLS (DoT) transport to the remote server. The certificate chain file is expected to be in PEM format. This option implies -S, and can only be used with -K.

-g: This option enables standard GSS-TSIG mode.

-H tlshostname: This option makes nsupdate use the provided hostname during remote server TLS certificate verification. Otherwise, the DNS server name is used. This option implies -S.

-i: This option forces interactive mode, even when standard input is not a terminal.

-k keyfile: This option indicates the file containing the TSIG authentication key. Keyfiles may be in two formats: a single file containing a named.conf-format key statement, which may be generated automatically by ddns-confgen; or a pair of files whose names are of the format K{name}.+157.+{random}.key and K{name}.+157.+{random}.private, which can be generated by dnssec-keygen. The -k option can also be used to specify a SIG(0) key used to authenticate Dynamic DNS update requests. In this case, the key specified is not an HMAC-MD5 key.

-K tlskeyfile: This option sets the key file for authenticated encryption for the DNS-over-TLS (DoT) transport with the remote server. The private key file is expected to be in PEM format. This option implies -S, and can only be used with -E.

-l: This option sets local-host only mode, which sets the server address to localhost (disabling the server so that the server address cannot be overridden). Connections to the local server use a TSIG key found in /usr/local/var/run/session.key, which is automatically generated by named if any local primary zone has set update-policy to local. The location of this key file can be overridden with the -k option.

-L level: This option sets the logging debug level. If zero, logging is disabled.

-o: This option is deprecated. Previously, it enabled a non-standards-compliant variant of GSS-TSIG that was used by Windows 2000. Since that OS is now long past its end of life, this option is now treated as a synonym for -g.

-O: This option enables Opportunistic TLS. When used, the remote peer’s TLS certificate will not be verified. This option should be used for debugging purposes only, and it is not recommended to use it in production. This option can not be used in conjuction with -A, and it implies -S.

-p port: This option sets the port to use for connections to a name server. The default is 53.

-P: This option prints the list of private BIND-specific resource record types whose format is understood by nsupdate. See also the -T option.

-r udpretries: This option sets the number of UDP retries. The default is 3. If zero, only one update request is made.

-S: This option indicates whether to use DNS-over-TLS (DoT) when querying name servers specified by server servername port syntax in the input file, and the primary server discovered through a SOA request. When the -K and -E options are used, then the specified TLS client certificate and private key pair are used for authentication (Mutual TLS). This option implies -v.

-t timeout: This option sets the maximum time an update request can take before it is aborted. The default is 300 seconds. If zero, the timeout is disabled for TCP mode. For UDP mode, the option -u takes precedence over this option, unless the option -u is set to zero, in which case the interval is computed from the -t timeout interval and the number of UDP retries. For UDP mode, the timeout can not be disabled, and will be rounded up to 1 second in case if both -t and -u are set to zero.

-T

This option prints the list of IANA standard resource record types whose format is understood by nsupdate. nsupdate exits after the lists are printed. The -T option can be combined with the -P option.

Other types can be entered using TYPEXXXXX where XXXXX is the decimal value of the type with no leading zeros. The rdata, if present, is parsed using the UNKNOWN rdata format, (<backslash> <hash> <space> <length> <space> <hexstring>).

-u udptimeout: This option sets the UDP retry interval. The default is 3 seconds. If zero, the interval is computed from the timeout interval and number of UDP retries.

-v: This option specifies that TCP should be used even for small update requests. By default, nsupdate uses UDP to send update requests to the name server unless they are too large to fit in a UDP request, in which case TCP is used. TCP may be preferable when a batch of update requests is made.

-V: This option prints the version number and exits.

-y [hmac:]keyname:secret

This option sets the literal TSIG authentication key. keyname is the name of the key, and secret is the base64 encoded shared secret. hmac is the name of the key algorithm; valid choices are hmac-md5, hmac-sha1, hmac-sha224, hmac-sha256, hmac-sha384, or hmac-sha512. If hmac is not specified, the default is hmac-md5, or if MD5 was disabled, hmac-sha256.

NOTE: Use of the -y option is discouraged because the shared secret is supplied as a command-line argument in clear text. This may be visible in the output from ps1 or in a history file maintained by the user’s shell.

Input Format

nsupdate reads input from filename or standard input. Each command is supplied on exactly one line of input. Some commands are for administrative purposes; others are either update instructions or prerequisite checks on the contents of the zone. These checks set conditions that some name or set of resource records (RRset) either exists or is absent from the zone. These conditions must be met if the entire update request is to succeed. Updates are rejected if the tests for the prerequisite conditions fail.

Every update request consists of zero or more prerequisites and zero or more updates. This allows a suitably authenticated update request to proceed if some specified resource records are either present or missing from the zone. A blank input line (or the send command) causes the accumulated commands to be sent as one Dynamic DNS update request to the name server.

The command formats and their meanings are as follows:

server servername port: This command sends all dynamic update requests to the name server servername. When no server statement is provided, nsupdate sends updates to the primary server of the correct zone. The MNAME field of that zone’s SOA record identify the primary server for that zone. port is the port number on servername where the dynamic update requests are sent. If no port number is specified, the default DNS port number of 53 is used.

Note

This command has no effect when GSS-TSIG is in use.
local address port: This command sends all dynamic update requests using the local address. When no local statement is provided, nsupdate sends updates using an address and port chosen by the system. port can also be used to force requests to come from a specific port. If no port number is specified, the system assigns one.
zone zonename: This command specifies that all updates are to be made to the zone zonename. If no zone statement is provided, nsupdate attempts to determine the correct zone to update based on the rest of the input.
class classname: This command specifies the default class. If no class is specified, the default class is IN.
ttl seconds: This command specifies the default time-to-live, in seconds, for records to be added. The value none clears the default TTL.
key hmac:keyname secret: This command specifies that all updates are to be TSIG-signed using the keyname-secret pair. If hmac is specified, it sets the signing algorithm in use. The default is hmac-md5; if MD5 was disabled, the default is hmac-sha256. The key command overrides any key specified on the command line via -y or -k.
gsstsig: This command uses GSS-TSIG to sign the updates. This is equivalent to specifying -g on the command line.
oldgsstsig: This command is deprecated and will be removed in a future release. Previously, it caused nsupdate to use the Windows 2000 version of GSS-TSIG to sign updates. It is now treated as a synonym for gsstsig.
realm [realm_name]: When using GSS-TSIG, this command specifies the use of realm_name rather than the default realm in krb5.conf. If no realm is specified, the saved realm is cleared.
check-names [boolean]: This command turns on or off check-names processing on records to be added. Check-names has no effect on prerequisites or records to be deleted. By default check-names processing is on. If check-names processing fails, the record is not added to the UPDATE message.
check-svbc [boolean]: This command turns on or off check-svcb processing on records to be added. Check-svcb has no effect on prerequisites or records to be deleted. By default check-svcb processing is on. If check-svcb processing fails, the record is not added to the UPDATE message.
prereq nxdomain domain-name: This command requires that no resource record of any type exist with the name domain-name.
prereq yxdomain domain-name: This command requires that domain-name exist (as at least one resource record, of any type).
prereq nxrrset domain-name class type: This command requires that no resource record exist of the specified type, class, and domain-name. If class is omitted, IN (Internet) is assumed.
prereq yxrrset domain-name class type: This command requires that a resource record of the specified type, class and domain-name exist. If class is omitted, IN (internet) is assumed.
prereq yxrrset domain-name class type data: With this command, the data from each set of prerequisites of this form sharing a common type, class, and domain-name are combined to form a set of RRs. This set of RRs must exactly match the set of RRs existing in the zone at the given type, class, and domain-name. The data are written in the standard text representation of the resource record’s RDATA.
update delete domain-name ttl class type data: This command deletes any resource records named domain-name. If type and data are provided, only matching resource records are removed. The Internet class is assumed if class is not supplied. The ttl is ignored, and is only allowed for compatibility.
update add domain-name ttl class type data: This command adds a new resource record with the specified ttl, class, and data.
show: This command displays the current message, containing all of the prerequisites and updates specified since the last send.
send: This command sends the current message. This is equivalent to entering a blank line.
answer: This command displays the answer.
debug: This command turns on debugging.
version: This command prints the version number.
help: This command prints a list of commands.

Lines beginning with a semicolon (;) are comments and are ignored.

Examples

The examples below show how nsupdate can be used to insert and delete resource records from the example.com zone. Notice that the input in each example contains a trailing blank line, so that a group of commands is sent as one dynamic update request to the primary name server for example.com.

# nsupdate
> update delete oldhost.example.com A
> update add newhost.example.com 86400 A 172.16.1.1
> send

Any A records for oldhost.example.com are deleted, and an A record for newhost.example.com with IP address 172.16.1.1 is added. The newly added record has a TTL of 1 day (86400 seconds).

# nsupdate
> prereq nxdomain nickname.example.com
> update add nickname.example.com 86400 CNAME somehost.example.com
> send

The prerequisite condition tells the name server to verify that there are no resource records of any type for nickname.example.com. If there are, the update request fails. If this name does not exist, a CNAME for it is added. This ensures that when the CNAME is added, it cannot conflict with the long-standing rule in RFC 1034 that a name must not exist as any other record type if it exists as a CNAME. (The rule has been updated for DNSSEC in RFC 2535 to allow CNAMEs to have RRSIG, DNSKEY, and NSEC records.)

Files

/etc/resolv.conf: Used to identify the default name server
/usr/local/var/run/session.key: Sets the default TSIG key for use in local-only mode
K{name}.+157.+{random}.key: Base-64 encoding of the HMAC-MD5 key created by dnssec-keygen.
K{name}.+157.+{random}.private: Base-64 encoding of the HMAC-MD5 key created by dnssec-keygen.

Bugs

The TSIG key is redundantly stored in two separate files. This is a consequence of nsupdate using the DST library for its cryptographic operations, and may change in future releases.

rndc-confgen - rndc key generation tool

Synopsis

rndc-confgen [-a] [-A algorithm] [-b keysize] [-c keyfile] [-h] [-k keyname] [-p port] [-s address] [-t chrootdir] [-u user]

Description

rndc-confgen generates configuration files for rndc. It can be used as a convenient alternative to writing the rndc.conf file and the corresponding controls and key statements in named.conf by hand. Alternatively, it can be run with the -a option to set up a rndc.key file and avoid the need for a rndc.conf file and a controls statement altogether.

Options

-a

This option sets automatic rndc configuration, which creates a file /usr/local/etc/rndc.key that is read by both rndc and named on startup. The rndc.key file defines a default command channel and authentication key allowing rndc to communicate with named on the local host with no further configuration.

If a more elaborate configuration than that generated by rndc-confgen -a is required, for example if rndc is to be used remotely, run rndc-confgen without the -a option and set up rndc.conf and named.conf as directed.

-A algorithm: This option specifies the algorithm to use for the TSIG key. Available choices are: hmac-md5, hmac-sha1, hmac-sha224, hmac-sha256, hmac-sha384, and hmac-sha512. The default is hmac-sha256.

-b keysize: This option specifies the size of the authentication key in bits. The size must be between 1 and 512 bits; the default is the hash size.

-c keyfile: This option is used with the -a option to specify an alternate location for rndc.key.

-h: This option prints a short summary of the options and arguments to rndc-confgen.

-k keyname: This option specifies the key name of the rndc authentication key. This must be a valid domain name. The default is rndc-key.

-p port: This option specifies the command channel port where named listens for connections from rndc. The default is 953.

-q: This option prevets printing the written path in automatic configuration mode.

-s address: This option specifies the IP address where named listens for command-channel connections from rndc. The default is the loopback address 127.0.0.1.

-t chrootdir: This option is used with the -a option to specify a directory where named runs chrooted. An additional copy of the rndc.key is written relative to this directory, so that it is found by the chrooted named.

-u user: This option is used with the -a option to set the owner of the generated rndc.key file. If -t is also specified, only the file in the chroot area has its owner changed.

Examples

To allow rndc to be used with no manual configuration, run:

rndc-confgen -a

To print a sample rndc.conf file and the corresponding controls and key statements to be manually inserted into named.conf, run:

rndc-confgen

rndc.conf - rndc configuration file

Synopsis

rndc.conf

Description

rndc.conf is the configuration file for rndc, the BIND 9 name server control utility. This file has a similar structure and syntax to named.conf. Statements are enclosed in braces and terminated with a semi-colon. Clauses in the statements are also semi-colon terminated. The usual comment styles are supported:

C style: /* */

C++ style: // to end of line

Unix style: # to end of line

rndc.conf is much simpler than named.conf. The file uses three statements: an options statement, a server statement, and a key statement.

The options statement contains five clauses. The default-server clause is followed by the name or address of a name server. This host is used when no name server is given as an argument to rndc. The default-key clause is followed by the name of a key, which is identified by a key statement. If no keyid is provided on the rndc command line, and no key clause is found in a matching server statement, this default key is used to authenticate the server’s commands and responses. The default-port clause is followed by the port to connect to on the remote name server. If no port option is provided on the rndc command line, and no port clause is found in a matching server statement, this default port is used to connect. The default-source-address and default-source-address-v6 clauses can be used to set the IPv4 and IPv6 source addresses respectively.

After the server keyword, the server statement includes a string which is the hostname or address for a name server. The statement has three possible clauses: key, port, and addresses. The key name must match the name of a key statement in the file. The port number specifies the port to connect to. If an addresses clause is supplied, these addresses are used instead of the server name. Each address can take an optional port. If an source-address or source-address-v6 is supplied, it is used to specify the IPv4 and IPv6 source address, respectively.

The key statement begins with an identifying string, the name of the key. The statement has two clauses. algorithm identifies the authentication algorithm for rndc to use; currently only HMAC-MD5 (for compatibility), HMAC-SHA1, HMAC-SHA224, HMAC-SHA256 (default), HMAC-SHA384, and HMAC-SHA512 are supported. This is followed by a secret clause which contains the base-64 encoding of the algorithm’s authentication key. The base-64 string is enclosed in double quotes.

There are two common ways to generate the base-64 string for the secret. The BIND 9 program rndc-confgen can be used to generate a random key, or the mmencode program, also known as mimencode, can be used to generate a base-64 string from known input. mmencode does not ship with BIND 9 but is available on many systems. See the Example section for sample command lines for each.

Example

options {
  default-server  localhost;
  default-key     samplekey;
};

server localhost {
  key             samplekey;
};

server testserver {
  key     testkey;
  addresses   { localhost port 5353; };
};

key samplekey {
  algorithm       hmac-sha256;
  secret          "6FMfj43Osz4lyb24OIe2iGEz9lf1llJO+lz";
};

key testkey {
  algorithm   hmac-sha256;
  secret      "R3HI8P6BKw9ZwXwN3VZKuQ==";
};

In the above example, rndc by default uses the server at localhost (127.0.0.1) and the key called “samplekey”. Commands to the localhost server use the “samplekey” key, which must also be defined in the server’s configuration file with the same name and secret. The key statement indicates that “samplekey” uses the HMAC-SHA256 algorithm and its secret clause contains the base-64 encoding of the HMAC-SHA256 secret enclosed in double quotes.

If rndc -s testserver is used, then rndc connects to the server on localhost port 5353 using the key “testkey”.

To generate a random secret with rndc-confgen:

rndc-confgen

A complete rndc.conf file, including the randomly generated key, is written to the standard output. Commented-out key and controls statements for named.conf are also printed.

To generate a base-64 secret with mmencode:

echo "known plaintext for a secret" | mmencode

Name Server Configuration

The name server must be configured to accept rndc connections and to recognize the key specified in the rndc.conf file, using the controls statement in named.conf. See the sections on the controls statement in the BIND 9 Administrator Reference Manual for details.

rndc - name server control utility

Synopsis

rndc [-b source-address] [-c config-file] [-k key-file] [-s server] [-p port] [-q] [-r] [-V] [-y server_key] [[-4] | [-6]] {command}

Description

rndc controls the operation of a name server. If rndc is invoked with no command line options or arguments, it prints a short summary of the supported commands and the available options and their arguments.

rndc communicates with the name server over a TCP connection, sending commands authenticated with digital signatures. In the current versions of rndc and named, the only supported authentication algorithms are HMAC-MD5 (for compatibility), HMAC-SHA1, HMAC-SHA224, HMAC-SHA256 (default), HMAC-SHA384, and HMAC-SHA512. They use a shared secret on each end of the connection, which provides TSIG-style authentication for the command request and the name server’s response. All commands sent over the channel must be signed by a server_key known to the server.

rndc reads a configuration file to determine how to contact the name server and decide what algorithm and key it should use.

Options

-4: This option indicates use of IPv4 only.

-6: This option indicates use of IPv6 only.

-b source-address: This option indicates source-address as the source address for the connection to the server. Multiple instances are permitted, to allow setting of both the IPv4 and IPv6 source addresses.

-c config-file: This option indicates config-file as the configuration file instead of the default, /usr/local/etc/rndc.conf.

-k key-file: This option indicates key-file as the key file instead of the default, /usr/local/etc/rndc.key. The key in /usr/local/etc/rndc.key is used to authenticate commands sent to the server if the config-file does not exist.

-s server: server is the name or address of the server which matches a server statement in the configuration file for rndc. If no server is supplied on the command line, the host named by the default-server clause in the options statement of the rndc configuration file is used.

-p port: This option instructs BIND 9 to send commands to TCP port port instead of its default control channel port, 953.

-q: This option sets quiet mode, where message text returned by the server is not printed unless there is an error.

-r: This option instructs rndc to print the result code returned by named after executing the requested command (e.g., ISC_R_SUCCESS, ISC_R_FAILURE, etc.).

-t timeout: This option sets the idle timeout period for rndc to timeout seconds. The default is 60 seconds, and the maximum settable value is 86400 seconds (1 day). If set to 0, there is no timeout.

-V: This option enables verbose logging.

-y server_key: This option indicates use of the key server_key from the configuration file. For control message validation to succeed, server_key must be known by named with the same algorithm and secret string. If no server_key is specified, rndc first looks for a key clause in the server statement of the server being used, or if no server statement is present for that host, then in the default-key clause of the options statement. Note that the configuration file contains shared secrets which are used to send authenticated control commands to name servers, and should therefore not have general read or write access.

Commands

A list of commands supported by rndc can be seen by running rndc without arguments.

Currently supported commands are:

addzone zone [class [view]] configuration

This command adds a zone while the server is running. This command requires the allow-new-zones option to be set to yes. The configuration string specified on the command line is the zone configuration text that would ordinarily be placed in named.conf.

The configuration is saved in a file called viewname.nzf (or, if named is compiled with liblmdb, an LMDB database file called viewname.nzd). viewname is the name of the view, unless the view name contains characters that are incompatible with use as a file name, in which case a cryptographic hash of the view name is used instead. When named is restarted, the file is loaded into the view configuration so that zones that were added can persist after a restart.

This sample addzone command adds the zone example.com to the default view:

rndc addzone example.com '{ type primary; file "example.com.db"; };'

(Note the brackets around and semi-colon after the zone configuration text.)

See also rndc delzone and rndc modzone.

delzone [-clean] zone [class [view]]

This command deletes a zone while the server is running.

If the -clean argument is specified, the zone’s master file (and journal file, if any) are deleted along with the zone. Without the -clean option, zone files must be deleted manually. (If the zone is of type secondary or stub, the files needing to be removed are reported in the output of the rndc delzone command.)

If the zone was originally added via rndc addzone, then it is removed permanently. However, if it was originally configured in named.conf, then that original configuration remains in place; when the server is restarted or reconfigured, the zone is recreated. To remove it permanently, it must also be removed from named.conf.

See also rndc addzone and rndc modzone.

dnssec (-status | -rollover -key id [-alg algorithm] [-when time] | -checkds [-key id [-alg algorithm]] [-when time] published | withdrawn)) zone [class [view]]

This command allows you to interact with the “dnssec-policy” of a given zone.

rndc dnssec -status show the DNSSEC signing state for the specified zone.

rndc dnssec -rollover allows you to schedule key rollover for a specific key (overriding the original key lifetime).

rndc dnssec -checkds informs named that the DS for a specified zone’s key-signing key has been confirmed to be published in, or withdrawn from, the parent zone. This is required in order to complete a KSK rollover. The -key id and -alg algorithm arguments can be used to specify a particular KSK, if necessary; if there is only one key acting as a KSK for the zone, these arguments can be omitted. The time of publication or withdrawal for the DS is set to the current time by default, but can be overridden to a specific time with the argument -when time, where time is expressed in YYYYMMDDHHMMSS notation.

dnstap (-reopen | -roll [number])

This command closes and re-opens DNSTAP output files.

rndc dnstap -reopen allows the output file to be renamed externally, so that named can truncate and re-open it.

rndc dnstap -roll causes the output file to be rolled automatically, similar to log files. The most recent output file has “.0” appended to its name; the previous most recent output file is moved to “.1”, and so on. If number is specified, then the number of backup log files is limited to that number.

dumpdb [-all | -cache | -zones | -adb | -bad | -expired | -fail] [view ...]: This command dumps the server’s caches (default) and/or zones to the dump file for the specified views. If no view is specified, all views are dumped. (See the dump-file option in the BIND 9 Administrator Reference Manual.)

fetchlimit [view]: This command dumps a list of servers that are currently being rate-limited as a result of fetches-per-server settings, and a list of domain names that are currently being rate-limited as a result of fetches-per-zone settings.

flush: This command flushes the server’s cache.

flushname name [view]: This command flushes the given name from the view’s DNS cache and, if applicable, from the view’s nameserver address database, bad server cache, and SERVFAIL cache.

flushtree name [view]: This command flushes the given name, and all of its subdomains, from the view’s DNS cache, address database, bad server cache, and SERVFAIL cache.

freeze [zone [class [view]]]

This command suspends updates to a dynamic zone. If no zone is specified, then all zones are suspended. This allows manual edits to be made to a zone normally updated by dynamic update, and causes changes in the journal file to be synced into the master file. All dynamic update attempts are refused while the zone is frozen.

Limitations

There is currently no way to provide the shared secret for a server_key without using the configuration file.

Several error messages could be clearer.

tsig-keygen - TSIG key generation tool

Synopsis

tsig-keygen [-a algorithm] [-h] [name]

Description

tsig-keygen is an utility that generates keys for use in TSIG signing. The resulting keys can be used, for example, to secure dynamic DNS updates to a zone, or for the rndc command channel.

A domain name can be specified on the command line to be used as the name of the generated key. If no name is specified, the default is tsig-key.

Options

-a algorithm: This option specifies the algorithm to use for the TSIG key. Available choices are: hmac-md5, hmac-sha1, hmac-sha224, hmac-sha256, hmac-sha384, and hmac-sha512. The default is hmac-sha256. Options are case-insensitive, and the “hmac-” prefix may be omitted.

-h: This option prints a short summary of options and arguments.

Manual Pages

arpaname - translate IP addresses to the corresponding ARPA names

Synopsis

Description

See Also

ddns-confgen - TSIG key generation tool

Synopsis

Description

Options

See Also

delv - DNS lookup and validation utility

Synopsis

Description

Simple Usage

Options

Query Options

Files

See Also

dig - DNS lookup utility

Synopsis

Description

Simple Usage

Options

Query Options

Multiple Queries

Return Codes

Files

See Also

Bugs

dnssec-cds - change DS records for a child zone based on CDS/CDNSKEY

Synopsis

Description

Options

Exit Status

Examples

See Also

dnssec-dsfromkey - DNSSEC DS RR generation tool

Synopsis

Description

Options

Example

Files

Caveat

See Also

dnssec-importkey - import DNSKEY records from external systems so they can be managed

Synopsis

Description

Options

Timing Options

Files

See Also

dnssec-keyfromlabel - DNSSEC key generation tool

Synopsis

Description

Options

Timing Options

Generated Key Files

See Also

dnssec-keygen: DNSSEC key generation tool

Synopsis

Description

Options

Timing Options

Generated Keys

Example

See Also

dnssec-revoke - set the REVOKED bit on a DNSSEC key

Synopsis

Description

Options

See Also

dnssec-settime: set the key timing metadata for a DNSSEC key

Synopsis

Description

Options

Timing Options

Key State Options

Printing Options

See Also

dnssec-signzone - DNSSEC zone signing tool