-d

Debug mode. This provides tracing information about the update requests that are made and the repliesreceived from the name server.

-D

Extra debug mode.

-i

Force interactive mode, even when standard input is not a terminal.

-k

The file containing the TSIG authentication key. Keyfiles may be in two formats: a single file containinga named.conf-format key statement, which may be generated automatically by ddns-confgen, or a pair offiles whose names are of the format K{name}.+157.+{random}.key and K{name}.+157.+{random}.private, whichcan be generated by dnssec-keygen. The -k may also be used to specify a SIG(0) key used to authenticateDynamic DNS update requests. In this case, the key specified is not an HMAC-MD5 key.

-l

Local-host only mode. This sets the server address to localhost (disabling the server so that the serveraddress cannot be overridden). Connections to the local server will use a TSIG key found in/var/run/named/session.key, which is automatically generated by named if any local master zone has setupdate-policy to local. The location of this key file can be overridden with the -k option.

-L

Set the logging debug level. If zero, logging is disabled.

-p

Set the port to use for connections to a name server. The default is 53.

-P

Print the list of private BIND-specific resource record types whose format is understood by nsupdate. Seealso the -T option.

-r

The number of UDP retries. The default is 3. If zero, only one update request will be made.

-R

Where to obtain randomness. If the operating system does not provide a /dev/random or equivalent device,the default source of randomness is keyboard input. randomdev specifies the name of a character device orfile containing random data to be used instead of the default. The special value keyboard indicates thatkeyboard input should be used. This option may be specified multiple times.

-t

The maximum time an update request can take before it is aborted. The default is 300 seconds. Zero can beused to disable the timeout.

-T

Print the list of IANA standard resource record types whose format is understood by nsupdate. nsupdatewill exit 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 noleading zeros. The rdata, if present, will be parsed using the UNKNOWN rdata format, (<backslash> <hash><space> <length> <space> <hexstring>).

-u

The UDP retry interval. The default is 3 seconds. If zero, the interval will be computed from the timeoutinterval and number of UDP retries.

-v

Use TCP even for small update requests. By default, nsupdate uses UDP to send update requests to the nameserver unless they are too large to fit in a UDP request in which case TCP will be used. TCP may bepreferable when a batch of update requests is made.

-V

Print the version number and exit.

-y

Literal TSIG authentication key. keyname is the name of the key, and secret is the base64 encoded sharedsecret. 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 wasdisabled hmac-sha256.NOTE: Use of the -y option is discouraged because the shared secret is supplied as a command line argumentin clear text. This may be visible in the output from ps(1) or in a history file maintained by the user'sshell.INPUT FORMATnsupdate reads input from filename or standard input. Each command is supplied on exactly one line of input.Some commands are for administrative purposes. The others are either update instructions or prerequisitechecks 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 isto succeed. Updates will be 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 suitablyauthenticated update request to proceed if some specified resource records are present or missing from thezone. A blank input line (or the send command) causes the accumulated commands to be sent as one Dynamic DNSupdate request to the name server.The command formats and their meaning are as follows:server {servername} [port]Sends all dynamic update requests to the name server servername. When no server statement is provided,nsupdate will send updates to the master server of the correct zone. The MNAME field of that zone's SOArecord will identify the master server for that zone. port is the port number on servername where thedynamic update requests get sent. If no port number is specified, the default DNS port number of 53 isused.local {address} [port]Sends all dynamic update requests using the local address. When no local statement is provided, nsupdatewill send updates using an address and port chosen by the system. port can additionally be used to makerequests come from a specific port. If no port number is specified, the system will assign one.zone {zonename}Specifies that all updates are to be made to the zone zonename. If no zone statement is provided, nsupdatewill attempt determine the correct zone to update based on the rest of the input.class {classname}Specify the default class. If no class is specified, the default class is IN.ttl {seconds}Specify the default time to live for records to be added. The value none will clear the default ttl.key [hmac:] {keyname} {secret}Specifies that all updates are to be TSIG-signed using the keynamesecret pair. If hmac is specified, thenit sets the signing algorithm in use; the default is hmac-md5 or if MD5 was disabled hmac-sha256. The keycommand overrides any key specified on the command line via -y or -k.gsstsigUse GSS-TSIG to sign the updated. This is equivalent to specifying -g on the command line.oldgsstsigUse the Windows 2000 version of GSS-TSIG to sign the updated. This is equivalent to specifying -o on thecommand line.realm {[realm_name]}When using GSS-TSIG use realm_name rather than the default realm in krb5.conf. If no realm is specifiedthe saved realm is cleared.check-names {[yes_or_no]}Turn on or off check-names processing on records to be added. Check-names has no effect on prerequisitesor records to be deleted. By default check-names processing is on. If check-names processing fails therecord will not be added to the UPDATE message.[prereq] nxdomain {domain-name}Requires that no resource record of any type exists with name domain-name.[prereq] yxdomain {domain-name}Requires that domain-name exists (has as at least one resource record, of any type).[prereq] nxrrset {domain-name} [class] {type}Requires that no resource record exists of the specified type, class and domain-name. If class is omitted,IN (internet) is assumed.[prereq] yxrrset {domain-name} [class] {type}This requires that a resource record of the specified type, class and domain-name must exist. If class isomitted, IN (internet) is assumed.[prereq] yxrrset {domain-name} [class] {type} {data...}The data from each set of prerequisites of this form sharing a common type, class, and domain-name arecombined to form a set of RRs. This set of RRs must exactly match the set of RRs existing in the zone atthe given type, class, and domain-name. The data are written in the standard text representation of theresource record's RDATA.[update] del[ete] {domain-name} [ttl] [class] [type [data...]]Deletes any resource records named domain-name. If type and data is provided, only matching resourcerecords will be removed. The internet class is assumed if class is not supplied. The ttl is ignored, andis only allowed for compatibility.[update] add {domain-name} {ttl} [class] {type} {data...}Adds a new resource record with the specified ttl, class and data.showDisplays the current message, containing all of the prerequisites and updates specified since the lastsend.sendSends the current message. This is equivalent to entering a blank line.answerDisplays the answer.debugTurn on debugging.versionPrint version number.helpPrint a list of commands.Lines beginning with a semicolon are comments and are ignored.EXAMPLESThe examples below show how nsupdate could be used to insert and delete resource records from the example.comzone. Notice that the input in each example contains a trailing blank line so that a group of commands aresent as one dynamic update request to the master name server for example.com.# nsupdate> update delete oldhost.example.com A> update add newhost.example.com 86400 A 172.16.1.1> sendAny A records for oldhost.example.com are deleted. And an A record for newhost.example.com with IP address172.16.1.1 is added. The newly-added record has a 1 day TTL (86400 seconds).# nsupdate> prereq nxdomain nickname.example.com> update add nickname.example.com 86400 CNAME somehost.example.com> sendThe prerequisite condition gets the name server to check that there are no resource records of any type fornickname.example.com. If there are, the update request fails. If this name does not exist, a CNAME for it isadded. This ensures that when the CNAME is added, it cannot conflict with the long-standing rule in RFC 1034that a name must not exist as any other record type if it exists as a CNAME. (The rule has been updated forDNSSEC in RFC 2535 to allow CNAMEs to have RRSIG, DNSKEY and NSEC records.)FILES/etc/resolv.confused to identify default name server/var/run/named/session.keysets the default TSIG key for use in local-only modeK{name}.+157.+{random}.keybase-64 encoding of HMAC-MD5 key created by dnssec-keygen(8).K{name}.+157.+{random}.privatebase-64 encoding of HMAC-MD5 key created by dnssec-keygen(8).