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<refentry id='ypbind8'>
  <refmeta>
    <refentrytitle>ypbind</refentrytitle>
    <manvolnum>8</manvolnum>
    <refmiscinfo class='sectdesc'>ypbind-mt</refmiscinfo>
  </refmeta>

  <refnamediv id='name'>
    <refname>ypbind</refname>
    <refpurpose>NIS binding process</refpurpose>
  </refnamediv>

  <refsynopsisdiv id='synopsis'>
  <cmdsynopsis>
    <command>ypbind</command>
      <arg choice='opt'>-c </arg>
      <group choice='opt'><arg choice='plain'>-d </arg><arg choice='plain'>-debug </arg></group>
      <arg choice='opt'>-verbose </arg>
      <group choice='opt'><arg choice='plain'>-n </arg><arg choice='plain'>-forground </arg></group>
      <arg choice='opt'>-broadcast </arg>
      <arg choice='opt'>-broken-server </arg>
      <arg choice='opt'>-ypset </arg>
      <arg choice='opt'>-ypsetme </arg>
      <arg choice='opt'>-no-ping </arg>
      <arg choice='opt'>-f <replaceable>configfile</replaceable></arg>
      <arg choice='opt'>-local-only </arg>
      <arg choice='opt'>-ping-interval <replaceable>ping-interval</replaceable></arg>
      <arg choice='opt'>-p <replaceable>port</replaceable></arg>
  </cmdsynopsis>
  <cmdsynopsis>
    <command>ypbind</command>
      <arg choice='plain'>--version </arg>
    </cmdsynopsis>
  </refsynopsisdiv>


  <refsect1 id='description'>
    <title>DESCRIPTION</title>
    <para>
      <command>ypbind</command> finds the server for NIS domains and
      maintains the NIS binding information. The client (normally the
      NIS routines in the standard C library) could get the information
      over RPC from <command>ypbind</command> or read the binding files.
      The binding files resides in the directory
      <filename>/var/yp/binding</filename> and are conventionally named
      <emphasis remap='B'>[domainname].[version]</emphasis>. The supported
      versions are 1, 2 and 3. There could be several such files since it
      is possible for an NIS client to be bound to more than one domain.
    </para>

    <para>
      After a binding has been established, <command>ypbind</command>
      will send YPPROC_DOMAIN requests to the current NIS server at 5 
      minutes intervals. If it doesn't get an response or the NIS server
      reports that he doesn't have this domain any longer,
      <command>ypbind</command> will search for a new NIS server.
      You could tell <command>ypbind</command> to use network broadcasts
      to find a new server, what is insecure, or you could give it a list
      of known secure servers. In this case <command>ypbind</command> will
      send a ping to all servers in the order in which they are listed in
      the config file and use the first one which answers.
    </para>

    <para>Unless the option
<option>-debug</option>
is used, ypbind detaches itself from the controlling terminal and puts
itself into background.
<command>ypbind</command>
uses
<citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
for logging errors and warnings.
At startup or when receiving signal SIGHUP,
<command>ypbind</command>
parses the file
<filename>/etc/yp.conf</filename>
and tries to use the entries for its initial binding.</para>

<para>A broadcast entry in the configuration file will overwrite a ypserver/server
entry and a ypserver/server entry broadcast. If all given server are down,
<command>ypbind</command>
will
<emphasis remap='B'>not</emphasis>
switch to use broadcast.
<command>ypbind</command>
will try at first
<filename>/etc/hosts</filename>
and then
<emphasis remap='B'>DNS</emphasis>
for resolving the hosts names from
<filename>/etc/yp.conf</filename>.
If
<command>ypbind</command>
couldn't reconfigure the search order, it will use only
<emphasis remap='B'>DNS</emphasis>.
If
<emphasis remap='B'>DNS</emphasis>
isn't available, you could only use IP-addresses in
<filename>/etc/hosts</filename>.
<command>ypbind</command>
could only reconfigure the search order with glibc 2.x.
If the
<option>-broadcast</option>
option is specified,
<command>ypbind</command>
will ignore the configuration file.
If the file does not exist or if there are no valid entries,
<command>ypbind</command>
exit.</para>

  </refsect1>

  <refsect1 id='options'>
    <title>OPTIONS</title>
    <variablelist>
      <varlistentry>
        <term><option>-broadcast</option></term>
        <listitem>
          <para>
            Send a broadcast to request the information needed to
            bind to a specific NIS server. With this option,
            <filename>/etc/yp.conf</filename> will be ignored.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
  <term><option>-ypset</option></term>
  <listitem>
<para>Allow
<emphasis remap='B'>root</emphasis>
from any remote machine to change the binding for a domain via the
<citerefentry><refentrytitle>ypset</refentrytitle><manvolnum>8</manvolnum></citerefentry>
command. By default, no one can change the binding. This option is really
insecure. If you change a binding for a domain, all the current known
servers for this domain will be forgotten. If the new server goes down,
<command>ypbind</command>
will use the old searchlist.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><option>-ypsetme</option></term>
  <listitem>
<para>The same as
<option>-ypset</option>,
but only
<emphasis remap='B'>root</emphasis>
on the local machine is allowed to change the binding. Such requests
are only allowed from
<emphasis remap='B'>loopback</emphasis>.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><option>-c</option></term>
  <listitem>
<para><command>ypbind</command>
only checks if the config file has syntax errors and exits.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><option>-d</option>, <option>-debug</option></term>
  <listitem>
<para>starts
<command>ypbind</command>
in debug mode.
<command>ypbind</command>
will not put itself into background, and error messages and debug
output are written to standard error.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><option>-n</option>, <option>-foreground</option></term>
  <listitem>
<para>
<command>ypbind</command>
will not put itself into backgroun.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><option>-v</option>, <option>-verbose</option></term>
  <listitem>
<para>Causes
<command>ypbind</command>
to syslog(2) any and all changes in the server its bound to.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><option>-broken-server</option></term>
  <listitem>
<para>Lets
<command>ypbind</command>
accept answers from servers running on an illegal port number. This should
usually be avoided, but is required by some
<citerefentry><refentrytitle>ypserv</refentrytitle><manvolnum>8</manvolnum></citerefentry>
versions.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><option>-no-ping</option></term>
  <listitem>
<para><command>ypbind</command>
will not check if the binding is alive. This option is for use with
dialup connections to prevent
<command>ypbind</command>
from keeping the connection unnecessarily open or causing auto-dials.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><option>-f</option> configfile</term>
  <listitem>
<para><command>ypbind</command>
will use
<emphasis remap='B'>configfile</emphasis>
and not
<filename>/etc/yp.conf</filename></para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><option>-local-only</option></term>
  <listitem>
<para><command>ypbind</command>
will only bind to the loopback device and is not reachable from
a remote network.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><option>-i</option>, <option>-ping-interval</option> ping-interval</term>
  <listitem>
<para>The default value for
<command>ypbind</command>
to check, if a NIS server is still reachable, is 20 seconds.
With this options another frequency in seconds can be specified.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><option>-p</option> port</term>
  <listitem>
<para>The privileged port number that
<command>ypbind</command>
should use to bind itself.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><option>--version</option></term>
  <listitem>
<para>Prints the version number</para>
  </listitem>
  </varlistentry>
</variablelist>

</refsect1>

<refsect1 id='files'><title>FILES</title>
<variablelist remap='TP'>
  <varlistentry>
  <term><filename>/etc/yp.conf</filename></term>
  <listitem>
<para>configuration file.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><filename>/var/yp/binding/[domainname].[version]</filename></term>
  <listitem>
<para>binding file containing information about each NIS domain.</para>
  </listitem>
  </varlistentry>
  <varlistentry>
  <term><filename>/var/run/ypbind.pid</filename></term>
  <listitem>
<para>contains the process id of the currently running
<command>ypbind</command>
master process.</para>
  </listitem>
  </varlistentry>
</variablelist>

</refsect1>

  <refsect1 id='see_also'>
    <title>SEE ALSO</title>
    <para>
      <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>domainname</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>yp.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>ypdomainname</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>ypwhich</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>ypserv</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>ypset</refentrytitle><manvolnum>8</manvolnum></citerefentry>
    </para>
  </refsect1>

  <refsect1 id='author'>
    <title>AUTHOR</title>
      <para>
        <emphasis remap='B'>ypbind-mt</emphasis> was written by
        Thorsten Kukuk &lt;kukuk@thkukuk.de&gt;.
      </para>
  </refsect1>
</refentry>