<para>BIND (<command>named</command>) is listening on port 53

	  <para>BIND (<command>named</command>) is listening on

	    and some other high-numbered port.  What is going on?</para>

	    some high-numbered ports.  What is going on?</para>

	    queries.  If you want to use port 53 for outgoing queries,

	    queries.  Recent versions of it choose a new, random UDP

	    either to get past a firewall or to make yourself feel

	    port for each query.  This may cause problems for some

	    better, you can try the following in

	    network configurations, especially if a firewall blocks

	    <filename>/etc/namedb/named.conf</filename>:</para>

	    incoming UDP packets on particular ports.  If you want to

	    get past that firewall, you can try the

	  <programlisting>options {

	    <literal>avoid-v4-udp-ports</literal> and

        query-source address * port 53;

	    <literal>avoid-v6-udp-ports</literal> options to avoid

};</programlisting>

	    selecting random port numbers within a blocked range.</para>

	  <para>You can replace the <literal>*</literal> with a single

	  <warning>

	    IP address if you want to tighten things further.</para>

	    <para>If a port number (like 53) is specified via the

	      <literal>query-source</literal> or

	      <literal>query-source-v6</literal> options in

	      <filename>/etc/namedb/named.conf</filename>, randomized

	      port selection will not be used.  It is strongly

	      recommended that these options not be used to specify

	      fixed port numbers.</para>

	  </warning>