NAME
nsupdate - dynamic DNS update utilitySYNOPSIS
nsupdate [-d] [-D] [-i] [-L level] [ [-g] | [ -o] | [-l] | [-y [hmac:]keyname:secret] | [ -k keyfile] ] [-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.OPTIONS
- -4
- This option sets use of IPv4 only.
- -6
- This option sets use of IPv6 only.
- -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.
- -g
- This option enables standard GSS-TSIG mode.
- -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.
- -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 /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 enables a non-standards-compliant variant of GSS-TSIG used by Windows 2000.
- -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.
- -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.- 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 uses the Windows 2000 version of GSS-TSIG to sign the updates. This is equivalent to specifying -o on the command line.
- 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.
- 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.
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
# nsupdate > prereq nxdomain nickname.example.com > update add nickname.example.com 86400 CNAME somehost.example.com > send
FILES
- /etc/resolv.conf
- Used to identify the default name server
- /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.
SEE ALSO
RFC 2136, RFC 3007, RFC 2104, RFC 2845, RFC 1034, RFC 2535, RFC 2931, named(8), dnssec-keygen(8), tsig-keygen(8).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.AUTHOR
Internet Systems ConsortiumCOPYRIGHT
2024, Internet Systems Consortium2024-02-11 | 9.18.24-1-Debian |