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<H1 ALIGN="CENTER">Setting which addresses and ports Apache uses</H1>

<p>When Apache starts, it connects to some port and address on the
local machine and waits for incoming requests. By default, it
listens to all addresses on the machine, and to the port
as specified by the <code>Port</code> directive in the server configuration.
However, it can be told to listen to more the one port, or to listen
to only selected addresses, or a combination. This is often combined
with the Virtual Host feature which determines how Apache
responds to different IP addresses, hostnames and ports.</p>

<p>The <code>Listen</code> directive tells the server to accept
incoming requests only on the specified port or address-and-port
combinations. If only a port number is specified in the
<code>Listen</code> directive, the server listens to the given port on
all interfaces, instead of the port given by the <code>Port</code>
directive. If an IP address is given as well as a port, the server
will listen on the given port and interface.  Multiple Listen
directives may be used to specify a number of addresses and ports to
listen to. The server will respond to requests from any of the listed
addresses and ports.</P>

<p>For example, to make the server accept connections on both port
80 and port 8000, use:
<PRE>
   Listen 80
   Listen 8000
</PRE>

To make the server accept connections on two specified
interfaces and port numbers, use
<PRE>
   Listen 192.170.2.1:80
   Listen 192.170.2.5:8000
</PRE>

<H2>How this works with Virtual Hosts</H2>

<p>Listen does not implement Virtual Hosts.  It only tells the
main server what addresses and ports to listen to.  If no
&lt;VirtualHost&gt; directives are used, the server will behave the
same for all accepted requests. However, &lt;VirtualHost&gt; can be
used to specify a different behavior for one or more of the addresses
and ports. To implement a VirtualHost, the server must first be told
to listen to the address and port to be used. Then a
&lt;VirtualHost&gt; section should be created for a specified address
and port to set the behavior of this virtual host. Note that if the
&lt;VirtualHost&gt; is set for an address and port that the server is
not listening to, it cannot be accessed.

<H2>See also</H2>

See also the documentation on
<a href="mod/mpm_common.html#listen">Listen directive</a>,
<A HREF="vhosts/">Virtual Hosts</A>,
<A HREF="mod/core.html#port">Port directive</A>,
<A HREF="dns-caveats.html">DNS Issues</A>
and
<A HREF="mod/core.html#virtualhost">&lt;VirtualHost&gt; section</A>.

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