nsupdate.1 (2010 09)

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nsupdate(1) nsupdate(1)

(BIND 9.3)

NAME

nsupdate - Dynamic DNS update utility

SYNOPSIS

nsupdate [-dv][-k

keyﬁle | -y keyname :secret][-r udpretries ][-t

timeout ]

[

-u udptimeout ][ﬁlename]

DESCRIPTION

nsupdate submits Dynamic DNS update requests to a name server, as deﬁned in RFC 2136. This

allows resource records to be added to 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 have to be in the same

zone. Requests are sent to the zone’s master server. This 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 or the SIG(0) record described in RFC 2535 and RFC 2931.

TSIG relies on a shared secret that should only be known to nsupdate and the name server. Currently,

the only supported encryption algorithm for TSIG is HMAC-MD5, which is deﬁned in RFC 2104.

Once other algorithms are deﬁned for

TSIG, applications will need to ensure they select the appropriate

algorithm as well as the key when authenticating each other. For instance, suitable

key{} and

server{} statements would be added to /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 will be using

TSIG authentication. 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. nsupdate does not read

/etc/named.conf.

Options

-d Operate in debug mode. This provides tracing information about the update requests that are

made and the replies received from the name server.

-k keyfile

Provide the shared secret needed to generate a TSIG record for authenticating Dynamic DNS

update requests. With this option, nsupdate reads the shared secret from the ﬁle keyﬁle,

whose name is of the form

Kname.+157.+random .private

For historical reasons, the ﬁle Kname.+157.+random.key must also be present. This

option is mutually exclusive with the -y option. -k may 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.

-r udpretries

Set the number of UDP retries. The default is 3. If set to zero only one update request will be

made.

-t timeout

Set the maximum time in seconds a update request can take before it is aborted. The default

is 300 seconds. Zero can be used to disable the timeout.

-u udptimeout

Set the UDP retry interval in seconds. The default is 3 seconds. If set to zero the interval will

be computed from the timeout interval and number of UDP retries.

-v Use a TCP connection to send update requests to the name server. By default, nsupdate

uses UDP to send update requests. This may be preferable when a batch of update requests is

made.

-y keyname:secret

Generate a signature from keyname and secret . keyname is the name of the key, and secret is

the base-64-encoded shared secret. The 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 ps(1) or in a history ﬁle maintained by the user’s shell.

HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1

Summary of content (4 pages)

PAGE 1
nsupdate(1) nsupdate(1) (BIND 9.3) NAME nsupdate - Dynamic DNS update utility SYNOPSIS nsupdate [-dv] [-k keyfile | -y keyname :secret] [-r udpretries ] [-t timeout ] [-u udptimeout ] [filename ] DESCRIPTION nsupdate submits Dynamic DNS update requests to a name server, as defined in RFC 2136. This allows resource records to be added to 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.
PAGE 2
nsupdate(1) nsupdate(1) (BIND 9.3) Operands filename A file of nsupdate commands, as described in the Input Format section. The default is standard input. Input Format nsupdate reads commands 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.
PAGE 3
nsupdate(1) nsupdate(1) (BIND 9.3) update delete domain-name class type data... Deletes any resource records named domain-name . If type and data are provided, only matching resource records will be removed. The Internet class (IN) is assumed if class is not supplied. update add domain-name ttl class type data... Adds a new resource record with the specified ttl , class and data . show Displays the current message, containing all the prerequisites and updates specified since the last send operation.
PAGE 4
nsupdate(1) nsupdate(1) (BIND 9.3) BIND 9 Administrator Reference Manual , available from the Internet Systems Consortium at http://www.isc.org/sw/bind/arm93.