2N/A - Copyright (C) 2004-2012, 2014, 2015 Internet Systems Consortium, Inc. ("ISC") 2N/A - Copyright (C) 2000-2003 Internet Software Consortium. 2N/A - Permission to use, copy, modify, and/or distribute this software for any 2N/A - purpose with or without fee is hereby granted, provided that the above 2N/A - copyright notice and this permission notice appear in all copies. 2N/A - THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH 2N/A - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY 2N/A - AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, 2N/A - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 2N/A - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE 2N/A - OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 2N/A - PERFORMANCE OF THIS SOFTWARE. 2N/A<
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div class="refentry" lang="en">
2N/A<
div class="refnamediv">
2N/A<
p><
span class="application">nsupdate</
span> — Dynamic DNS update utility</
p>
2N/A<
div class="refsynopsisdiv">
2N/A<
div class="cmdsynopsis"><
p><
code class="command">nsupdate</
code> [<
code class="option">-d</
code>] [<
code class="option">-D</
code>] [<
code class="option">-L <
em class="replaceable"><
code>level</
code></
em></
code>] [[<
code class="option">-g</
code>] | [<
code class="option">-o</
code>] | [<
code class="option">-l</
code>] | [<
code class="option">-y <
em class="replaceable"><
code>[<
span class="optional">hmac:</
span>]keyname:secret</
code></
em></
code>] | [<
code class="option">-k <
em class="replaceable"><
code>keyfile</
code></
em></
code>]] [<
code class="option">-t <
em class="replaceable"><
code>timeout</
code></
em></
code>] [<
code class="option">-u <
em class="replaceable"><
code>udptimeout</
code></
em></
code>] [<
code class="option">-r <
em class="replaceable"><
code>udpretries</
code></
em></
code>] [<
code class="option">-R <
em class="replaceable"><
code>randomdev</
code></
em></
code>] [<
code class="option">-v</
code>] [<
code class="option">-T</
code>] [<
code class="option">-P</
code>] [<
code class="option">-V</
code>] [filename]</
p></
div>
2N/A<
div class="refsect1" lang="en">
2N/A<
a name="id2543499"></
a><
h2>DESCRIPTION</
h2>
2N/A<
p><
span><
strong class="command">nsupdate</
strong></
span>
2N/A is used to submit Dynamic DNS Update requests as defined in RFC 2136
2N/A This allows resource records to be added or removed from a zone
2N/A without manually editing the zone file.
2N/A A single update request can contain requests to add or remove more than
2N/A Zones that are under dynamic control via
2N/A <
span><
strong class="command">nsupdate</
strong></
span>
2N/A or a DHCP server should not be edited by hand.
2N/A conflict with dynamic updates and cause data to be lost.
2N/A The resource records that are dynamically added or removed with
2N/A <
span><
strong class="command">nsupdate</
strong></
span>
2N/A have to be in the same zone.
2N/A Requests are sent to the zone's master server.
2N/A This is identified by the MNAME field of the zone's SOA record.
2N/A Transaction signatures can be used to authenticate the Dynamic
2N/A DNS updates. These use the TSIG resource record type described
2N/A in RFC 2845 or the SIG(0) record described in RFC 2535 and
2N/A RFC 2931 or GSS-TSIG as described in RFC 3645.
2N/A a shared secret that should only be known to
2N/A <
span><
strong class="command">nsupdate</
strong></
span> and the name server.
2N/A For instance, suitable <
span class="type">key</
span> and
2N/A <
span class="type">server</
span> statements would be added to
2N/A can associate the appropriate secret key and algorithm with
2N/A the IP address of the client application that will be using
2N/A TSIG authentication. You can use <
span><
strong class="command">ddns-confgen</
strong></
span>
2N/A to generate suitable configuration fragments.
2N/A <
span><
strong class="command">nsupdate</
strong></
span>
2N/A uses the <
code class="option">-y</
code> or <
code class="option">-k</
code> options
2N/A to provide the TSIG shared secret. These options are mutually exclusive.
2N/A SIG(0) uses public key cryptography.
2N/A To use a SIG(0) key, the public key must be stored in a KEY
2N/A record in a zone served by the name server.
2N/A GSS-TSIG uses Kerberos credentials. Standard GSS-TSIG mode
2N/A is switched on with the <
code class="option">-g</
code> flag. A
2N/A non-standards-compliant variant of GSS-TSIG used by Windows
2N/A 2000 can be switched on with the <
code class="option">-o</
code> flag.
2N/A<
div class="refsect1" lang="en">
2N/A<
a name="id2543573"></
a><
h2>OPTIONS</
h2>
2N/A<
div class="variablelist"><
dl>
2N/A<
dt><
span class="term">-d</
span></
dt>
2N/A Debug mode. This provides tracing information about the
2N/A update requests that are made and the replies received
2N/A from the name server.
2N/A<
dt><
span class="term">-D</
span></
dt>
2N/A<
dt><
span class="term">-k <
em class="replaceable"><
code>keyfile</
code></
em></
span></
dt>
2N/A The file containing the TSIG authentication key.
2N/A Keyfiles may be in two formats: a single file containing
2N/A a <
code class="filename">
named.conf</
code>-format <
span><
strong class="command">key</
strong></
span>
2N/A statement, which may be generated automatically by
2N/A <
span><
strong class="command">ddns-confgen</
strong></
span>, or a pair of files whose names are
2N/A of the format <
code class="filename">K{name}.+157.+{random}.key</
code> and
2N/A <
code class="filename">K{name}.+157.+{random}.private</
code>, which can be
2N/A generated by <
span><
strong class="command">dnssec-keygen</
strong></
span>.
2N/A The <
code class="option">-k</
code> may also be used to specify a SIG(0) key used
2N/A to authenticate Dynamic DNS update requests. In this case, the key
2N/A specified is not an HMAC-MD5 key.
2N/A<
dt><
span class="term">-l</
span></
dt>
2N/A Local-host only mode. This sets the server address to
2N/A localhost (disabling the <
span><
strong class="command">server</
strong></
span> so that the server
2N/A address cannot be overridden). Connections to the local server will
2N/A which is automatically generated by <
span><
strong class="command">named</
strong></
span> if any
2N/A local master zone has set <
span><
strong class="command">update-policy</
strong></
span> to
2N/A <
span><
strong class="command">local</
strong></
span>. The location of this key file can be
2N/A overridden with the <
code class="option">-k</
code> option.
2N/A<
dt><
span class="term">-L <
em class="replaceable"><
code>level</
code></
em></
span></
dt>
2N/A Set the logging debug level. If zero, logging is disabled.
2N/A<
dt><
span class="term">-p <
em class="replaceable"><
code>port</
code></
em></
span></
dt>
2N/A Set the port to use for connections to a name server. The
2N/A<
dt><
span class="term">-P</
span></
dt>
2N/A Print the list of private BIND-specific resource record
2N/A types whose format is understood
2N/A by <
span><
strong class="command">nsupdate</
strong></
span>. See also
2N/A the <
code class="option">-T</
code> option.
2N/A<
dt><
span class="term">-r <
em class="replaceable"><
code>udpretries</
code></
em></
span></
dt>
2N/A The number of UDP retries. The default is 3. If zero, only
2N/A one update request will be made.
2N/A<
dt><
span class="term">-R <
em class="replaceable"><
code>randomdev</
code></
em></
span></
dt>
2N/A Where to obtain randomness. If the operating system
2N/A does not provide a <
code class="filename">/
dev/
random</
code> or
2N/A equivalent device, the default source of randomness is keyboard
2N/A input. <
code class="filename">randomdev</
code> specifies the name of
2N/A a character device or file containing random data to be used
2N/A instead of the default. The special value
2N/A <
code class="filename">keyboard</
code> indicates that keyboard input
2N/A should be used. This option may be specified multiple times.
2N/A<
dt><
span class="term">-t <
em class="replaceable"><
code>timeout</
code></
em></
span></
dt>
2N/A The maximum time an update request can take before it is
2N/A aborted. The default is 300 seconds. Zero can be used to
2N/A disable the timeout.
2N/A<
dt><
span class="term">-T</
span></
dt>
2N/A Print the list of IANA standard resource record types
2N/A whose format is understood by <
span><
strong class="command">nsupdate</
strong></
span>.
2N/A <
span><
strong class="command">nsupdate</
strong></
span> will exit after the lists are
2N/A printed. The <
code class="option">-T</
code> option can be combined
2N/A with the <
code class="option">-P</
code> option.
2N/A Other types can be entered using "TYPEXXXXX" where "XXXXX" is the
2N/A decimal value of the type with no leading zeros. The rdata,
2N/A if present, will be parsed using the UNKNOWN rdata format,
2N/A (<backslash> <hash> <space> <length>
2N/A <space> <hexstring>).
2N/A<
dt><
span class="term">-u <
em class="replaceable"><
code>udptimeout</
code></
em></
span></
dt>
2N/A The UDP retry interval. The default is 3 seconds. If zero,
2N/A the interval will be computed from the timeout interval and
2N/A number of UDP retries.
2N/A<
dt><
span class="term">-v</
span></
dt>
2N/A Use TCP even for small update requests.
2N/A By default, <
span><
strong class="command">nsupdate</
strong></
span>
2N/A uses UDP to send update requests to the name server unless they are too
2N/A large to fit in a UDP request in which case TCP will be used.
2N/A TCP may be preferable when a batch of update requests is made.
2N/A<
dt><
span class="term">-V</
span></
dt>
2N/A Print the version number and exit.
2N/A<
dt><
span class="term">-y <
em class="replaceable"><
code>[<
span class="optional">hmac:</
span>]keyname:secret</
code></
em></
span></
dt>
2N/A Literal TSIG authentication key.
2N/A <
em class="parameter"><
code>keyname</
code></
em> is the name of the key, and
2N/A <
em class="parameter"><
code>secret</
code></
em> is the base64 encoded shared secret.
2N/A <
em class="parameter"><
code>hmac</
code></
em> is the name of the key algorithm;
2N/A valid choices are <
code class="literal">hmac-md5</
code>,
2N/A <
code class="literal">hmac-sha1</
code>, <
code class="literal">hmac-sha224</
code>,
2N/A <
code class="literal">hmac-sha256</
code>, <
code class="literal">hmac-sha384</
code>, or
2N/A <
code class="literal">hmac-sha512</
code>. If <
em class="parameter"><
code>hmac</
code></
em>
2N/A is not specified, the default is <
code class="literal">hmac-md5</
code>.
2N/A NOTE: Use of the <
code class="option">-y</
code> option is discouraged because the
2N/A shared secret is supplied as a command line argument in clear text.
2N/A This may be visible in the output from
2N/A <
span class="citerefentry"><
span class="refentrytitle">ps</
span>(1)</
span>
2N/A or in a history file maintained by the user's shell.
2N/A<
div class="refsect1" lang="en">
2N/A<
a name="id2544090"></
a><
h2>INPUT FORMAT</
h2>
2N/A<
p><
span><
strong class="command">nsupdate</
strong></
span>
2N/A <
em class="parameter"><
code>filename</
code></
em>
2N/A Each command is supplied on exactly one line of input.
2N/A Some commands are for administrative purposes.
2N/A The others are either update instructions or prerequisite checks on the
2N/A contents of the zone.
2N/A These checks set conditions that some name or set of
2N/A resource records (RRset) either exists or is absent from the zone.
2N/A These conditions must be met if the entire update request is to succeed.
2N/A Updates will be rejected if the tests for the prerequisite conditions
2N/A Every update request consists of zero or more prerequisites
2N/A and zero or more updates.
2N/A This allows a suitably authenticated update request to proceed if some
2N/A specified resource records are present or missing from the zone.
2N/A A blank input line (or the <
span><
strong class="command">send</
strong></
span> command)
2N/A accumulated commands to be sent as one Dynamic DNS update request to the
2N/A The command formats and their meaning are as follows:
2N/A<
div class="variablelist"><
dl>
2N/A<
dt><
span class="term">
2N/A <
span><
strong class="command">server</
strong></
span>
2N/A Sends all dynamic update requests to the name server
2N/A <
em class="parameter"><
code>servername</
code></
em>.
2N/A When no server statement is provided,
2N/A <
span><
strong class="command">nsupdate</
strong></
span>
2N/A will send updates to the master server of the correct zone.
2N/A The MNAME field of that zone's SOA record will identify the
2N/A server for that zone.
2N/A <
em class="parameter"><
code>port</
code></
em>
2N/A is the port number on
2N/A <
em class="parameter"><
code>servername</
code></
em>
2N/A where the dynamic update requests get sent.
2N/A If no port number is specified, the default DNS port number of
2N/A<
dt><
span class="term">
2N/A <
span><
strong class="command">local</
strong></
span>
2N/A Sends all dynamic update requests using the local
2N/A <
em class="parameter"><
code>address</
code></
em>.
2N/A When no local statement is provided,
2N/A <
span><
strong class="command">nsupdate</
strong></
span>
2N/A will send updates using an address and port chosen by the
2N/A <
em class="parameter"><
code>port</
code></
em>
2N/A can additionally be used to make requests come from a specific
2N/A If no port number is specified, the system will assign one.
2N/A<
dt><
span class="term">
2N/A <
span><
strong class="command">zone</
strong></
span>
2N/A Specifies that all updates are to be made to the zone
2N/A <
em class="parameter"><
code>zonename</
code></
em>.
2N/A <
em class="parameter"><
code>zone</
code></
em>
2N/A statement is provided,
2N/A <
span><
strong class="command">nsupdate</
strong></
span>
2N/A will attempt determine the correct zone to update based on the
2N/A<
dt><
span class="term">
2N/A <
span><
strong class="command">class</
strong></
span>
2N/A Specify the default class.
2N/A If no <
em class="parameter"><
code>class</
code></
em> is specified, the
2N/A <
em class="parameter"><
code>IN</
code></
em>.
2N/A<
dt><
span class="term">
2N/A <
span><
strong class="command">ttl</
strong></
span>
2N/A Specify the default time to live for records to be added.
2N/A The value <
em class="parameter"><
code>none</
code></
em> will clear the default
2N/A<
dt><
span class="term">
2N/A <
span><
strong class="command">key</
strong></
span>
2N/A Specifies that all updates are to be TSIG-signed using the
2N/A <
em class="parameter"><
code>keyname</
code></
em> <
em class="parameter"><
code>secret</
code></
em> pair.
2N/A If <
em class="parameter"><
code>hmac</
code></
em> is specified, then it sets the
2N/A signing algorithm in use; the default is
2N/A <
code class="literal">hmac-md5</
code>. The <
span><
strong class="command">key</
strong></
span>
2N/A command overrides any key specified on the command line via
2N/A <
code class="option">-y</
code> or <
code class="option">-k</
code>.
2N/A<
dt><
span class="term">
2N/A <
span><
strong class="command">gsstsig</
strong></
span>
2N/A Use GSS-TSIG to sign the updated. This is equivalent to
2N/A specifying <
code class="option">-g</
code> on the commandline.
2N/A<
dt><
span class="term">
2N/A <
span><
strong class="command">oldgsstsig</
strong></
span>
2N/A Use the Windows 2000 version of GSS-TSIG to sign the updated.
2N/A This is equivalent to specifying <
code class="option">-o</
code> on the
2N/A<
dt><
span class="term">
2N/A <
span><
strong class="command">realm</
strong></
span>
2N/A {[<
span class="optional">realm_name</
span>]}
2N/A When using GSS-TSIG use <
em class="parameter"><
code>realm_name</
code></
em> rather
2N/A than the default realm in <
code class="filename">
krb5.conf</
code>. If no
2N/A realm is specified the saved realm is cleared.
2N/A<
dt><
span class="term">
2N/A <
span><
strong class="command">check-names</
strong></
span>
2N/A {[<
span class="optional">yes_or_no</
span>]}
2N/A Turn on or off check-names processing on records to
2N/A 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 will not be added to the UPDATE message.
<
span><
strong class="command">[<
span class="optional">prereq</
span>] nxdomain</
strong></
span>
Requires that no resource record of any type exists with name
<
em class="parameter"><
code>domain-name</
code></
em>.
<
span><
strong class="command">[<
span class="optional">prereq</
span>] yxdomain</
strong></
span>
<
em class="parameter"><
code>domain-name</
code></
em>
exists (has as at least one resource record, of any type).
<
span><
strong class="command">[<
span class="optional">prereq</
span>] nxrrset</
strong></
span>
Requires that no resource record exists of the specified
<
em class="parameter"><
code>type</
code></
em>,
<
em class="parameter"><
code>class</
code></
em>
<
em class="parameter"><
code>domain-name</
code></
em>.
<
em class="parameter"><
code>class</
code></
em>
is omitted, IN (internet) is assumed.
<
span><
strong class="command">[<
span class="optional">prereq</
span>] yxrrset</
strong></
span>
This requires that a resource record of the specified
<
em class="parameter"><
code>type</
code></
em>,
<
em class="parameter"><
code>class</
code></
em>
<
em class="parameter"><
code>domain-name</
code></
em>
<
em class="parameter"><
code>class</
code></
em>
is omitted, IN (internet) is assumed.
<
span><
strong class="command">[<
span class="optional">prereq</
span>] yxrrset</
strong></
span>
<
em class="parameter"><
code>data</
code></
em>
from each set of prerequisites of this form
<
em class="parameter"><
code>type</
code></
em>,
<
em class="parameter"><
code>class</
code></
em>,
<
em class="parameter"><
code>domain-name</
code></
em>
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
<
em class="parameter"><
code>type</
code></
em>,
<
em class="parameter"><
code>class</
code></
em>,
<
em class="parameter"><
code>domain-name</
code></
em>.
<
em class="parameter"><
code>data</
code></
em>
are written in the standard text representation of the resource
<
span><
strong class="command">[<
span class="optional">update</
span>] del[<
span class="optional">ete</
span>]</
strong></
span>
Deletes any resource records named
<
em class="parameter"><
code>domain-name</
code></
em>.
<
em class="parameter"><
code>type</
code></
em>
<
em class="parameter"><
code>data</
code></
em>
is provided, only matching resource records will be removed.
The internet class is assumed if
<
em class="parameter"><
code>class</
code></
em>
<
em class="parameter"><
code>ttl</
code></
em>
is ignored, and is only allowed for compatibility.
<
span><
strong class="command">[<
span class="optional">update</
span>] add</
strong></
span>
Adds a new resource record with the specified
<
em class="parameter"><
code>ttl</
code></
em>,
<
em class="parameter"><
code>class</
code></
em>
<
em class="parameter"><
code>data</
code></
em>.
<
span><
strong class="command">show</
strong></
span>
Displays the current message, containing all of the
updates specified since the last send.
<
span><
strong class="command">send</
strong></
span>
Sends the current message. This is equivalent to entering a
<
span><
strong class="command">answer</
strong></
span>
<
span><
strong class="command">debug</
strong></
span>
<
span><
strong class="command">version</
strong></
span>
<
span><
strong class="command">help</
strong></
span>
Print a list of commands.
Lines beginning with a semicolon are comments and are ignored.
<
div class="refsect1" lang="en">
<
a name="id2545012"></
a><
h2>EXAMPLES</
h2>
The examples below show how
<
span><
strong class="command">nsupdate</
strong></
span>
could be used to insert and delete resource records from the
Notice that the input in each example contains a trailing blank line so
a group of commands are sent as one dynamic update request to the
<
pre class="programlisting">
with IP address 172.16.1.1 is added.
The newly-added record has a 1 day TTL (86400 seconds).
<
pre class="programlisting">
The prerequisite condition gets the name server to check that there
are no resource records of any type for
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.)
<
div class="refsect1" lang="en">
<
a name="id2545056"></
a><
h2>FILES</
h2>
<
div class="variablelist"><
dl>
<
dt><
span class="term"><
code class="constant">/
etc/
resolv.conf</
code></
span></
dt>
used to identify default name server
sets the default TSIG key for use in local-only mode
<
dt><
span class="term"><
code class="constant">K{name}.+157.+{random}.key</
code></
span></
dt>
base-64 encoding of HMAC-MD5 key created by
<
span class="citerefentry"><
span class="refentrytitle">dnssec-keygen</
span>(8)</
span>.
<
dt><
span class="term"><
code class="constant">K{name}.+157.+{random}.private</
code></
span></
dt>
base-64 encoding of HMAC-MD5 key created by
<
span class="citerefentry"><
span class="refentrytitle">dnssec-keygen</
span>(8)</
span>.
<
div class="refsect1" lang="en">
<
a name="id2545142"></
a><
h2>SEE ALSO</
h2>
<
em class="citetitle">RFC 2136</
em>,
<
em class="citetitle">RFC 3007</
em>,
<
em class="citetitle">RFC 2104</
em>,
<
em class="citetitle">RFC 2845</
em>,
<
em class="citetitle">RFC 1034</
em>,
<
em class="citetitle">RFC 2535</
em>,
<
em class="citetitle">RFC 2931</
em>,
<
span class="citerefentry"><
span class="refentrytitle">named</
span>(8)</
span>,
<
span class="citerefentry"><
span class="refentrytitle">ddns-confgen</
span>(8)</
span>,
<
span class="citerefentry"><
span class="refentrytitle">dnssec-keygen</
span>(8)</
span>.
<
div class="refsect1" lang="en">
<
a name="id2545200"></
a><
h2>BUGS</
h2>
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