nsupdate.docbook

bind 9.3结合mysql数据库

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<refentry>
<refentryinfo>
<date>Jun 30, 2000</date>
</refentryinfo>
<refmeta>
<refentrytitle>nsupdate</refentrytitle>
<manvolnum>8</manvolnum>
<refmiscinfo>BIND9</refmiscinfo>
</refmeta>
<refnamediv>
<refname>nsupdate</refname>
<refpurpose>Dynamic DNS update utility</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>nsupdate</command>
<arg><option>-d</option></arg>
<group>
  <arg><option>-y <replaceable class="parameter">keyname:secret</replaceable></option></arg>
  <arg><option>-k <replaceable class="parameter">keyfile</replaceable></option></arg>
</group>
<arg><option>-t <replaceable class="parameter">timeout</replaceable></option></arg>
<arg><option>-u <replaceable class="parameter">udptimeout</replaceable></option></arg>
<arg><option>-r <replaceable class="parameter">udpretries</replaceable></option></arg>
<arg><option>-v</option></arg>
<arg>filename</arg>
</cmdsynopsis>
</refsynopsisdiv>

<refsect1>
<title>DESCRIPTION</title>
<para>
<command>nsupdate</command>
is used to submit Dynamic DNS Update requests as defined in RFC2136
to a name server.
This allows resource records to be added 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.
</para>
<para>
Zones that are under dynamic control via
<command>nsupdate</command>
or a DHCP server should not be edited by hand.
Manual edits could
conflict with dynamic updates and cause data to be lost.
</para>
<para>
The resource records that are dynamically added or removed with
<command>nsupdate</command>
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.
</para>
<para>
The
<option>-d</option>
option makes
<command>nsupdate</command>
operate in debug mode.
This provides tracing information about the update requests that are
made and the replies received from the name server.
</para>
<para>
Transaction signatures can be used to authenticate the Dynamic DNS
updates.
These use the TSIG resource record type described in RFC2845 or the
SIG(0) record described in RFC3535 and RFC2931.
TSIG relies on a shared secret that should only be known to
<command>nsupdate</command> 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
<type>key</type>
and
<type>server</type>
statements would be added to
<filename>/etc/named.conf</filename>
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.
<command>nsupdate</command>
does not read
<filename>/etc/named.conf</filename>.
</para>
<para>
<command>nsupdate</command>
uses the
<option>-y</option>
or
<option>-k</option>
option (with an HMAC-MD5 key) to provide the shared secret needed to generate
a TSIG record for authenticating Dynamic DNS update requests.
These options are mutually exclusive.
With the
<option>-k</option>
option,
<command>nsupdate</command>
reads the shared secret from the file
<parameter>keyfile</parameter>,
whose name is of the form 
<filename>K{name}.+157.+{random}.private</filename>.
For historical
reasons, the file 
<filename>K{name}.+157.+{random}.key</filename>
must also be present.  When the
<option>-y</option>
option is used, a signature is generated from
<parameter>keyname:secret.</parameter>
<parameter>keyname</parameter>
is the name of the key,
and
<parameter>secret</parameter>
is the base64 encoded shared secret.
Use of the
<option>-y</option>
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
<citerefentry>
<refentrytitle>ps</refentrytitle><manvolnum>1
</manvolnum>
</citerefentry>
or in a history file maintained by the user's shell.
</para>
<para>
The <option>-k</option> 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.
</para>
<para>
By default
<command>nsupdate</command>
uses UDP to send update requests to the name server unless they are too
large to fit in a UDP request in which case TCP will be used.
The
<option>-v</option>
option makes
<command>nsupdate</command>
use a TCP connection.
This may be preferable when a batch of update requests is made.
</para>
<para>The <option>-t</option> option sets the maximum time a update request can
take before it is aborted.  The default is 300 seconds.  Zero can be used
to disable the timeout.
</para>
<para>The <option>-u</option> option sets the UDP retry interval.  The default is
3 seconds.  If zero the interval will be computed from the timeout interval
and number of UDP retries.
</para>
<para>The <option>-r</option> option sets the number of UDP retries. The default is
3.  If zero only one update request will be made.
</para>
</refsect1>

<refsect1>
<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 (or the <command>send</command> command) 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 chosen 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>
</listitem>
</varlistentry>

<varlistentry><term>
<cmdsynopsis>
<command>class</command>
<arg choice="req">classname</arg>
</cmdsynopsis>
</term>
<listitem>
<para>
Specify the default class.
If no <parameter>class</parameter> is specified the default class is
<parameter>IN</parameter>.
</para>
</listitem>
</varlistentry>

<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>
</listitem>
</varlistentry>

<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>
</listitem>