6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.1//EN">

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<refentry>

1753d3c4d74241a847794f7e7cfd94cc79be6600Evan Hunt<refentryinfo>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<date>Jun 30, 2000</date>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed</refentryinfo>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<refmeta>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<refentrytitle>nsupdate</refentrytitle>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<manvolnum>8</manvolnum>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<refmiscinfo>BIND9</refmiscinfo>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed</refmeta>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<refnamediv>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<refname>nsupdate</refname>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<refpurpose>Dynamic DNS update utility</refpurpose>

87a58323be6bc89b50c216ac01c3e92f4721ab7cAutomatic Updater</refnamediv>

938440694b33cd752e9e4b71a526368b4811c177Tinderbox User<refsynopsisdiv>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<cmdsynopsis>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<command>nsupdate</command>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<arg><option>-d</option></arg>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<group>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed <arg><option>-y <replaceable class="parameter">keyname:secret</replaceable></option></arg>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed <arg><option>-k <replaceable class="parameter">keyfile</replaceable></option></arg>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed</group>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<arg><option>-v</option></arg>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<arg>filename</arg>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed</cmdsynopsis>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed</refsynopsisdiv>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<refsect1>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<title>DESCRIPTION</title>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<para>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<command>nsupdate</command>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedis used to submit Dynamic DNS Update requests as defined in RFC2136

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedto a name server.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedThis allows resource records to be added or removed from a zone

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedwithout manually editing the zone file.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedA single update request can contain requests to add or remove more than one

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedresource record.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed</para>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<para>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedZones that are under dynamic control via

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<command>nsupdate</command>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedor a DHCP server should not be edited by hand.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedManual edits could

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedconflict with dynamic updates and cause data to be lost.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed</para>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<para>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedThe resource records that are dynamically added or removed with

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<command>nsupdate</command>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedhave to be in the same zone.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedRequests are sent to the zone's master server.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedThis is identified by the MNAME field of the zone's SOA record.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed</para>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<para>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedThe

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<option>-d</option>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedoption makes

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<command>nsupdate</command>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedoperate in debug mode.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedThis provides tracing information about the update requests that are

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedmade and the replies received from the name server.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed</para>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<para>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedTransaction signatures can be used to authenticate the Dynamic DNS

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedupdates.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedThese use the TSIG resource record type described in RFC2845.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedThe signatures rely on a shared secret that should only be known to

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<command>nsupdate</command>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedand the name server.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedCurrently, the only supported encryption algorithm for TSIG is

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedHMAC-MD5, which is defined in RFC 2104.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedOnce other algorithms are defined for TSIG, applications will need to

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedensure they select the appropriate algorithm as well as the key when

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedauthenticating each other.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedFor instance suitable

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<type>key</type>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedand

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<type>server</type>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedstatements would be added to

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<filename>/etc/named.conf</filename>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedso that the name server can associate the appropriate secret key

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedand algorithm with the IP address of the

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedclient application that will be using TSIG authentication.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<command>nsupdate</command>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reeddoes not read

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<filename>/etc/named.conf</filename>.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed</para>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<para>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<command>nsupdate</command>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reeduses the

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<option>-y</option>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedor

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<option>-k</option>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedoption to provide the shared secret needed to generate a TSIG record

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedfor authenticating Dynamic DNS update requests.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedThese options are mutually exclusive.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedWith the

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<option>-k</option>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedoption,

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<command>nsupdate</command>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedreads the shared secret from the file

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<parameter>keyfile</parameter>,

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedwhose name is of the form

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<filename>K{name}.+157.+{random}.private</filename>.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedFor historical

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedreasons, the file

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<filename>K{name}.+157.+{random}.key</filename>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedmust also be present. When the

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<option>-y</option>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedoption is used, a signature is generated from

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<parameter>keyname:secret.</parameter>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<parameter>keyname</parameter>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedis the name of the key,

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedand

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<parameter>secret</parameter>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedis the base64 encoded shared secret.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedUse of the

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<option>-y</option>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedoption is discouraged because the shared secret is supplied as a command

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedline argument in clear text.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedThis may be visible in the output from

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<citerefentry>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<refentrytitle>ps</refentrytitle><manvolnum>1

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed</manvolnum>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed</citerefentry>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedor in a history file maintained by the user's shell.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed</para>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<para>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedBy default

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<command>nsupdate</command>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reeduses UDP to send update requests to the name server.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedThe

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<option>-v</option>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reedoption makes

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<command>nsupdate</command>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reeduse a TCP connection.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy ReedThis may be preferable when a batch of update requests is made.

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed</para>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed</refsect1>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<refsect1>

6db1357c34f26079dc2516b02d712df228e3db99Jeremy Reed<title>INPUT FORMAT</title>

<para>

<command>nsupdate</command>

reads input from

<parameter>filename</parameter>

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 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 will be rejected if the tests for the prerequisite conditions fail.

</para>

<para>

Every update request consists of zero or more prerequisites

and zero or more updates.

This allows a suitably authenticated update request to proceed if some

specified resource records are present or missing from the zone.

A blank input line causes the accumulated commands to be sent as one Dynamic

DNS update request to the name server.

</para>

<para>

The command formats and their meaning are as follows:

<variablelist>

<varlistentry><term>

<cmdsynopsis>

<command>server</command>

<arg choice="req">servername</arg>

<arg choice="opt">port</arg>

</cmdsynopsis>

</term>

<listitem>

<para>

Sends all dynamic update requests to the name server

<parameter>servername</parameter>.

When no server statement is provided,

<command>nsupdate</command>

will send updates to the master server of the correct zone.

The MNAME field of that zone's SOA record will identify the master

server for that zone.

<parameter>port</parameter>

is the port number on

<parameter>servername</parameter>

where the dynamic update requests get sent.

If no port number is specified, the default DNS port number of 53 is

used.

</para>

<varlistentry><term>

<cmdsynopsis>

<command>local</command>

<arg choice="req">address</arg>

<arg choice="opt">port</arg>

</cmdsynopsis>

</term>

<listitem>

<para>

Sends all dynamic update requests using the local

<parameter>address</parameter>.

When no local statement is provided,

<command>nsupdate</command>

will send updates using an address and port choosen by the system.

<parameter>port</parameter>

can additionally be used to make requests come from a specific port.

If no port number is specified, the system will assign one.

<varlistentry><term>

<cmdsynopsis>

<command>zone</command>

<arg choice="req">zonename</arg>

</cmdsynopsis>

</term>

<listitem>

<para>

Specifies that all updates are to be made to the zone

<parameter>zonename</parameter>.

If no

<parameter>zone</parameter>

statement is provided,

<command>nsupdate</command>

will attempt determine the correct zone to update based on the rest of the input.

</para>

<varlistentry><term>

<cmdsynopsis>

<command>key</command>

<arg choice="req">name</arg>

<arg choice="req">secret</arg>

</cmdsynopsis>

</term>

<listitem>

<para>

Specifies that all updates are to be TSIG signed using the

<parameter>keyname</parameter> <parameter>keysecret</parameter> pair.

The <command>key</command> command

overrides any key specified on the command line via

<option>-y</option> or <option>-k</option>.

</para>

<varlistentry><term>

<cmdsynopsis>

<command>prereq nxdomain</command>

<arg choice="req">domain-name</arg>

</cmdsynopsis>

</term>

<listitem>

<para>

Requires that no resource record of any type exists with name

<parameter>domain-name</parameter>.

</para>

<varlistentry><term>

<cmdsynopsis>

<command>prereq yxdomain</command>

<arg choice="req">domain-name</arg>

</cmdsynopsis>

</term>

<listitem>

<para>

Requires that

<parameter>domain-name</parameter>

exists (has as at least one resource record, of any type).

</para>

<varlistentry><term>

<cmdsynopsis>

<command>prereq nxrrset</command>

<arg choice="req">domain-name</arg>

<arg choice="opt">class</arg>

<arg choice="req">type</arg>

</cmdsynopsis>

</term>

<listitem>

<para>

Requires that no resource record exists of the specified

<parameter>type</parameter>,

<parameter>class</parameter>

and

<parameter>domain-name</parameter>.

If

<parameter>class</parameter>

is omitted, IN (internet) is assumed.

<varlistentry><term>

<cmdsynopsis>

<command>prereq yxrrset</command>

<arg choice="req">domain-name</arg>

<arg choice="opt">class</arg>

<arg choice="req">type</arg>

</cmdsynopsis>

</term>

<listitem>

<para>

This requires that a resource record of the specified

<parameter>type</parameter>,

<parameter>class</parameter>

and

<parameter>domain-name</parameter>

must exist.

If

<parameter>class</parameter>

is omitted, IN (internet) is assumed.

</para>

<varlistentry><term>

<cmdsynopsis>

<command>prereq yxrrset</command>

<arg choice="req">domain-name</arg>

<arg choice="opt">class</arg>

<arg choice="req">type</arg>

<arg choice="req" rep="repeat">data</arg>

</cmdsynopsis>

</term>

<listitem>

<para>

The

<parameter>data</parameter>

from each set of prerequisites of this form

sharing a common

<parameter>type</parameter>,

<parameter>class</parameter>,

and

<parameter>domain-name</parameter>

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

<parameter>type</parameter>,

<parameter>class</parameter>,

and

<parameter>domain-name</parameter>.

The

<parameter>data</parameter>

are written in the standard text representation of the resource record's

RDATA.

</para>

<varlistentry><term>

<cmdsynopsis>

<command>update delete</command>

<arg choice="req">domain-name</arg>

<arg choice="opt">ttl</arg>

<arg choice="opt">class</arg>

<arg choice="opt">type <arg choice="opt" rep="repeat">data</arg></arg>

</cmdsynopsis>

</term>

<listitem>

<para>

Deletes any resource records named

<parameter>domain-name</parameter>.

If

<parameter>type</parameter>

and

<parameter>data</parameter>

is provided, only matching resource records will be removed.

The internet class is assumed if

<parameter>class</parameter>

is not supplied. The

<parameter>ttl</parameter>

is ignored, and is only allowed for compatibility.

</para>

<varlistentry><term>

<cmdsynopsis>

<command>update add</command>

<arg choice="req">domain-name</arg>

<arg choice="req">ttl</arg>

<arg choice="opt">class</arg>

<arg choice="req">type</arg>

<arg choice="req" rep="repeat">data</arg>

</cmdsynopsis>

</term>

<listitem>

<para>

Adds a new resource record with the specified

<parameter>ttl</parameter>,

<parameter>class</parameter>

and

<parameter>data</parameter>.

</para>

</listitem>

</variablelist>

<para>

Lines beginning with a semicolon are comments, and are ignored.

</para>

</refsect1>

<refsect1>

<title>EXAMPLES</title>

<para>

The examples below show how

<command>nsupdate</command>

could be used to insert and delete resource records from the

<type>example.com</type>

zone.

Notice that the input in each example contains a trailing blank line so that

a group of commands are sent as one dynamic update request to the

master name server for

<type>example.com</type>.

<programlisting>

# nsupdate

> update delete oldhost.example.com A

> update add newhost.example.com 86400 A 172.16.1.1

>

</programlisting>

</para>

<para>

Any A records for

<type>oldhost.example.com</type>

are deleted.

and an A record for

<type>newhost.example.com</type>

it IP address 172.16.1.1 is added.

The newly-added record has a 1 day TTL (86400 seconds)

<programlisting>

# nsupdate

> prereq nxdomain nickname.example.com

> update add nickname.example.com CNAME somehost.example.com

>

</programlisting>

</para>

<para>

The prerequisite condition gets the name server to check that there

are no resource records of any type for

<type>nickname.example.com</type>.

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 RFC1034 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 RFC2535 to allow CNAMEs to have

SIG, KEY and NXT records.)

</para>

</refsect1>

<refsect1>

<title>FILES</title>

<variablelist>

<varlistentry><term><constant>/etc/resolv.conf</constant></term>

<listitem>

<para>

used to identify default name server

</para>

</listitem>

<varlistentry><term><constant>K{name}.+157.+{random}.key</constant></term>

<listitem>

<para>

base-64 encoding of HMAC-MD5 key created by

<citerefentry>

<refentrytitle>dnssec-keygen</refentrytitle><manvolnum>8</manvolnum>

</citerefentry>.

</para>

</listitem>

<varlistentry><term><constant>K{name}.+157.+{random}.private</constant></term>

<listitem>

<para>

base-64 encoding of HMAC-MD5 key created by

<citerefentry>

<refentrytitle>dnssec-keygen</refentrytitle><manvolnum>8</manvolnum>

</citerefentry>.

</para>

</listitem>

</variablelist>

</refsect1>

<refsect1>

<title>SEE ALSO</title>

<para>

<citerefentry>

<refentrytitle>RFC2136</refentrytitle>

</citerefentry>,

<citerefentry>

<refentrytitle>RFC3007</refentrytitle>

</citerefentry>,

<citerefentry>

<refentrytitle>RFC2104</refentrytitle>

</citerefentry>,

<citerefentry>

<refentrytitle>RFC2845</refentrytitle>

</citerefentry>,

<citerefentry>

<refentrytitle>RFC1034</refentrytitle>

</citerefentry>,

<citerefentry>

<refentrytitle>RFC2535</refentrytitle>

</citerefentry>,

<citerefentry>

<refentrytitle>named</refentrytitle><manvolnum>8</manvolnum>

</citerefentry>,

<citerefentry>

<refentrytitle>dnssec-keygen</refentrytitle><manvolnum>8</manvolnum>

</citerefentry>.

</refsect1>

<refsect1>

<title>BUGS</title>

<para>

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.

</para>

</refsect1>

</refentry>