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286N/A<
tr><
th colspan="3" align="center"><
span class="application">nsupdate</
span></
th></
tr>
286N/A<
td width="20%" align="left">
286N/A<
th width="60%" align="center">Manual pages</
th>
286N/A<
div class="refentry" lang="en">
286N/A<
div class="refnamediv">
524N/A<
p><
span class="application">nsupdate</
span> — Dynamic DNS update utility</
p>
286N/A<
div class="refsynopsisdiv">
286N/A<
div class="cmdsynopsis"><
p><
code class="command">nsupdate</
code> [<
code class="option">-d</
code>] [<
code class="option">-D</
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>
286N/A<
div class="refsect1" lang="en">
286N/A<
a name="id2653819"></
a><
h2>DESCRIPTION</
h2>
286N/A<
p><
span><
strong class="command">nsupdate</
strong></
span>
286N/A is used to submit Dynamic DNS Update requests as defined in RFC 2136
286N/A This allows resource records to be added or removed from a zone
286N/A without manually editing the zone file.
286N/A A single update request can contain requests to add or remove more than
286N/A Zones that are under dynamic control via
286N/A <
span><
strong class="command">nsupdate</
strong></
span>
286N/A or a DHCP server should not be edited by hand.
286N/A conflict with dynamic updates and cause data to be lost.
286N/A The resource records that are dynamically added or removed with
286N/A <
span><
strong class="command">nsupdate</
strong></
span>
286N/A have to be in the same zone.
286N/A Requests are sent to the zone's master server.
286N/A This is identified by the MNAME field of the zone's SOA record.
286N/A <
code class="option">-d</
code>
286N/A <
span><
strong class="command">nsupdate</
strong></
span>
286N/A This provides tracing information about the update requests that are
286N/A made and the replies received from the name server.
286N/A The <
code class="option">-D</
code> option makes <
span><
strong class="command">nsupdate</
strong></
span>
286N/A report additional debugging information to <
code class="option">-d</
code>.
286N/A The <
code class="option">-L</
code> option with an integer argument of zero or
286N/A higher sets the logging debug level. If zero, logging is disabled.
286N/A Transaction signatures can be used to authenticate the Dynamic
286N/A DNS updates. These use the TSIG resource record type described
286N/A in RFC 2845 or the SIG(0) record described in RFC 2535 and
293N/A RFC 2931 or GSS-TSIG as described in RFC 3645. TSIG relies on
293N/A a shared secret that should only be known to
286N/A <
span><
strong class="command">nsupdate</
strong></
span> and the name server. Currently,
286N/A the only supported encryption algorithm for TSIG is HMAC-MD5,
293N/A which is defined in RFC 2104. Once other algorithms are
286N/A defined for TSIG, applications will need to ensure they select
286N/A the appropriate algorithm as well as the key when authenticating
286N/A each other. For instance, suitable <
span class="type">key</
span> and
293N/A <
span class="type">server</
span> statements would be added to
293N/A can associate the appropriate secret key and algorithm with
293N/A the IP address of the client application that will be using
293N/A TSIG authentication. SIG(0) uses public key cryptography.
293N/A To use a SIG(0) key, the public key must be stored in a KEY
293N/A record in a zone served by the name server.
293N/A <
span><
strong class="command">nsupdate</
strong></
span> does not read
286N/A GSS-TSIG uses Kerberos credentials. Standard GSS-TSIG mode
286N/A is switched on with the <
code class="option">-g</
code> flag. A
286N/A non-standards-compliant variant of GSS-TSIG used by Windows
286N/A 2000 can be switched on with the <
code class="option">-o</
code> flag.
286N/A<
p><
span><
strong class="command">nsupdate</
strong></
span>
286N/A uses the <
code class="option">-y</
code> or <
code class="option">-k</
code> option
286N/A to provide the shared secret needed to generate a TSIG record
286N/A for authenticating Dynamic DNS update requests, default type
286N/A HMAC-MD5. These options are mutually exclusive.
286N/A When the <
code class="option">-y</
code> option is used, a signature is
286N/A [<
span class="optional"><
em class="parameter"><
code>hmac:</
code></
em></
span>]<
em class="parameter"><
code>keyname:secret.</
code></
em>
286N/A <
em class="parameter"><
code>keyname</
code></
em> is the name of the key, and
286N/A <
em class="parameter"><
code>secret</
code></
em> is the base64 encoded shared secret.
286N/A <
em class="parameter"><
code>hmac</
code></
em> is the name of the key algorithm;
286N/A valid choices are <
code class="literal">hmac-md5</
code>,
286N/A <
code class="literal">hmac-sha1</
code>, <
code class="literal">hmac-sha224</
code>,
286N/A <
code class="literal">hmac-sha256</
code>, <
code class="literal">hmac-sha384</
code>, or
286N/A <
code class="literal">hmac-sha512</
code>. If <
em class="parameter"><
code>hmac</
code></
em>
286N/A is not specified, the default is <
code class="literal">hmac-md5</
code>.
293N/A NOTE: Use of the <
code class="option">-y</
code> option is discouraged because the
293N/A shared secret is supplied as a command line argument in clear text.
286N/A This may be visible in the output from
286N/A <
span class="citerefentry"><
span class="refentrytitle">ps</
span>(1)</
span>
286N/A or in a history file maintained by the user's shell.
286N/A <
code class="option">-k</
code> option, <
span><
strong class="command">nsupdate</
strong></
span> reads
293N/A the shared secret from the file <
em class="parameter"><
code>keyfile</
code></
em>.
286N/A Keyfiles may be in two formats: a single file containing
293N/A a <
code class="filename">
named.conf</
code>-format <
span><
strong class="command">key</
strong></
span>
293N/A statement, which may be generated automatically by
293N/A <
span><
strong class="command">ddns-confgen</
strong></
span>, or a pair of files whose names are
293N/A of the format <
code class="filename">K{name}.+157.+{random}.key</
code> and
293N/A <
code class="filename">K{name}.+157.+{random}.private</
code>, which can be
293N/A generated by <
span><
strong class="command">dnssec-keygen</
strong></
span>.
293N/A The <
code class="option">-k</
code> may also be used to specify a SIG(0) key used
293N/A to authenticate Dynamic DNS update requests. In this case, the key
293N/A specified is not an HMAC-MD5 key.
293N/A <
span><
strong class="command">nsupdate</
strong></
span> can be run in a local-host only mode
293N/A using the <
code class="option">-l</
code> flag. This sets the server address to
293N/A localhost (disabling the <
span><
strong class="command">server</
strong></
span> so that the server
293N/A address cannot be overridden). Connections to the local server will
293N/A which is automatically generated by <
span><
strong class="command">named</
strong></
span> if any
293N/A local master zone has set <
span><
strong class="command">update-policy</
strong></
span> to
293N/A <
span><
strong class="command">local</
strong></
span>. The location of this key file can be
293N/A overridden with the <
code class="option">-k</
code> option.
524N/A By default, <
span><
strong class="command">nsupdate</
strong></
span>
524N/A uses UDP to send update requests to the name server unless they are too
524N/A large to fit in a UDP request in which case TCP will be used.
524N/A <
code class="option">-v</
code>
524N/A <
span><
strong class="command">nsupdate</
strong></
span>
286N/A This may be preferable when a batch of update requests is made.
286N/A The <
code class="option">-p</
code> sets the default port number to use for
286N/A connections to a name server. The default is 53.
286N/A The <
code class="option">-t</
code> option sets the maximum time an update request
286N/A take before it is aborted. The default is 300 seconds. Zero can be
286N/A to disable the timeout.
286N/A The <
code class="option">-u</
code> option sets the UDP retry interval. The default
286N/A 3 seconds. If zero, the interval will be computed from the timeout
286N/A and number of UDP retries.
286N/A The <
code class="option">-r</
code> option sets the number of UDP retries. The
286N/A 3. If zero, only one update request will be made.
286N/A The <
code class="option">-R <
em class="replaceable"><
code>randomdev</
code></
em></
code> option
286N/A specifies a source of randomness. If the operating system
286N/A equivalent device, the default source of randomness is keyboard
286N/A input. <
code class="filename">randomdev</
code> specifies the name of
286N/A a character device or file containing random data to be used
286N/A instead of the default. The special value
286N/A <
code class="filename">keyboard</
code> indicates that keyboard input
286N/A should be used. This option may be specified multiple times.
286N/A Other types can be entered using "TYPEXXXXX" where "XXXXX" is the
286N/A decimal value of the type with no leading zeros. The rdata,
286N/A if present, will be parsed using the UNKNOWN rdata format,
286N/A (<backslash> <hash> <space> <length>
524N/A <space> <hexstring>).
286N/A The <
code class="option">-T</
code> and <
code class="option">-P</
code> options print out
286N/A lists of non-meta types for which the type-specific presentation
286N/A formats are known. <
code class="option">-T</
code> prints out the list of
286N/A IANA-assigned types. <
code class="option">-P</
code> prints out the list of
286N/A private types specific to <
span><
strong class="command">named</
strong></
span>. These options
286N/A may be combined. <
span><
strong class="command">nsupdate</
strong></
span> will exit after the
286N/A The -V option causes <
span><
strong class="command">nsupdate</
strong></
span> to print the
286N/A version number and exit.
286N/A<
div class="refsect1" lang="en">
286N/A<
a name="id2681008"></
a><
h2>INPUT FORMAT</
h2>
286N/A<
p><
span><
strong class="command">nsupdate</
strong></
span>
286N/A <
em class="parameter"><
code>filename</
code></
em>
286N/A Each command is supplied on exactly one line of input.
286N/A Some commands are for administrative purposes.
286N/A The others are either update instructions or prerequisite checks on the
286N/A These checks set conditions that some name or set of
286N/A resource records (RRset) either exists or is absent from the zone.
293N/A These conditions must be met if the entire update request is to succeed.
286N/A Updates will be rejected if the tests for the prerequisite conditions
286N/A Every update request consists of zero or more prerequisites
286N/A and zero or more updates.
286N/A This allows a suitably authenticated update request to proceed if some
286N/A specified resource records are present or missing from the zone.
286N/A A blank input line (or the <
span><
strong class="command">send</
strong></
span> command)
286N/A accumulated commands to be sent as one Dynamic DNS update request to the
286N/A The command formats and their meaning are as follows:
286N/A<
div class="variablelist"><
dl>
286N/A <
span><
strong class="command">server</
strong></
span>
286N/A Sends all dynamic update requests to the name server
286N/A <
em class="parameter"><
code>servername</
code></
em>.
286N/A When no server statement is provided,
286N/A <
span><
strong class="command">nsupdate</
strong></
span>
293N/A will send updates to the master server of the correct zone.
286N/A The MNAME field of that zone's SOA record will identify the
286N/A <
em class="parameter"><
code>port</
code></
em>
286N/A <
em class="parameter"><
code>servername</
code></
em>
286N/A where the dynamic update requests get sent.
286N/A If no port number is specified, the default DNS port number of
286N/A <
span><
strong class="command">local</
strong></
span>
293N/A Sends all dynamic update requests using the local
286N/A <
em class="parameter"><
code>address</
code></
em>.
286N/A When no local statement is provided,
286N/A <
span><
strong class="command">nsupdate</
strong></
span>
286N/A will send updates using an address and port chosen by the
286N/A <
em class="parameter"><
code>port</
code></
em>
286N/A can additionally be used to make requests come from a specific
286N/A If no port number is specified, the system will assign one.
286N/A <
span><
strong class="command">zone</
strong></
span>
286N/A Specifies that all updates are to be made to the zone
286N/A <
em class="parameter"><
code>zonename</
code></
em>.
286N/A <
em class="parameter"><
code>zone</
code></
em>
286N/A <
span><
strong class="command">nsupdate</
strong></
span>
286N/A will attempt determine the correct zone to update based on the
286N/A <
span><
strong class="command">class</
strong></
span>
286N/A Specify the default class.
286N/A If no <
em class="parameter"><
code>class</
code></
em> is specified, the
286N/A <
em class="parameter"><
code>IN</
code></
em>.
286N/A <
span><
strong class="command">ttl</
strong></
span>
286N/A Specify the default time to live for records to be added.
286N/A The value <
em class="parameter"><
code>none</
code></
em> will clear the default
286N/A <
span><
strong class="command">key</
strong></
span>
286N/A Specifies that all updates are to be TSIG-signed using the
286N/A <
em class="parameter"><
code>keyname</
code></
em> <
em class="parameter"><
code>secret</
code></
em> pair.
286N/A If <
em class="parameter"><
code>hmac</
code></
em> is specified, then it sets the
286N/A signing algorithm in use; the default is
286N/A <
code class="literal">hmac-md5</
code>. The <
span><
strong class="command">key</
strong></
span>
286N/A command overrides any key specified on the command line via
286N/A <
code class="option">-y</
code> or <
code class="option">-k</
code>.
286N/A <
span><
strong class="command">gsstsig</
strong></
span>
286N/A Use GSS-TSIG to sign the updated. This is equivalent to
286N/A specifying <
code class="option">-g</
code> on the commandline.
286N/A <
span><
strong class="command">oldgsstsig</
strong></
span>
286N/A Use the Windows 2000 version of GSS-TSIG to sign the updated.
286N/A This is equivalent to specifying <
code class="option">-o</
code> on the
286N/A <
span><
strong class="command">realm</
strong></
span>
286N/A {[<
span class="optional">realm_name</
span>]}
286N/A When using GSS-TSIG use <
em class="parameter"><
code>realm_name</
code></
em> rather
286N/A than the default realm in <
code class="filename">
krb5.conf</
code>. If no
286N/A realm is specified the saved realm is cleared.
286N/A <
span><
strong class="command">check-names</
strong></
span>
286N/A {[<
span class="optional">yes_or_no</
span>]}
286N/A Turn on or off check-names processing on records to
286N/A be added. Check-names has no effect on prerequisites
286N/A or records to be deleted. By default check-names
286N/A processing is on. If check-names processing fails
286N/A the record will not be added to the UPDATE message.
286N/A <
span><
strong class="command">[<
span class="optional">prereq</
span>] nxdomain</
strong></
span>
286N/A 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="id2682224"></
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="id2682274"></
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="id2682357"></
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="id2682414"></
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
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p style="text-align: center;">BIND 9.11.0pre-alpha</
p>