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5205N/A<manualpage metafile="bind.xml.meta">

5205N/A

5205N/A <title>Binding</title>

5205N/A

6226N/A <summary>

5205N/A <p>Configuring Apache to listen on specific addresses and ports.</p>

5205N/A </summary>

5205N/A

5205N/A <seealso><a href="vhosts/">Virtual Hosts</a></seealso>

6226N/A <seealso><a href="dns-caveats.html">DNS Issues</a></seealso>

5205N/A

5205N/A <section id="overview">

5205N/A <title>Overview</title>

5205N/A

5205N/A <related>

5205N/A <modulelist>

5205N/A <module>core</module>

5205N/A <module>mpm_common</module>

5205N/A </modulelist>

5205N/A <directivelist>

5205N/A <directive module="core" type="section">VirtualHost</directive>

5205N/A <directive module="mpm_common">Listen</directive>

5205N/A </directivelist>

5205N/A </related>

5205N/A

5205N/A

5205N/A <p>When Apache starts, it binds to some port and address on

5205N/A the local machine and waits for incoming requests. By default,

6226N/A it listens to all addresses on the machine. However, it needs to

5205N/A be told to listen on specific ports, or to listen on only selected

5205N/A addresses, or a combination. This is often combined with the

5205N/A Virtual Host feature which determines how Apache responds to

5205N/A different IP addresses, hostnames and ports.</p>

5205N/A

5205N/A <p>The <directive module="mpm_common">Listen</directive>

5205N/A directive tells the server to accept

5205N/A incoming requests only on the specified port or

5205N/A address-and-port combinations. If only a port number is

5205N/A specified in the <directive module="mpm_common">Listen</directive>

5205N/A directive, the server

5205N/A listens to the given port on all interfaces. If an IP address

5205N/A is given as well as a port, the server will listen on the given

5205N/A port and interface. Multiple <directive

5205N/A module="mpm_common">Listen</directive> directives may be used to

5205N/A specify a number of addresses and ports to listen on. The

5205N/A server will respond to requests from any of the listed

5205N/A addresses and ports.</p>

5205N/A

5205N/A <p>For example, to make the server accept connections on both

5205N/A port 80 and port 8000, use:</p>

5205N/A

5205N/A <example>

5205N/A Listen 80<br />

5205N/A Listen 8000

5205N/A </example>

5205N/A

5205N/A <p>To make the server accept connections on two specified

5205N/A interfaces and port numbers, use</p>

5205N/A

5205N/A <example>

5205N/A Listen 192.170.2.1:80<br />

5205N/A Listen 192.170.2.5:8000

5205N/A </example>

5205N/A

5205N/A <p>IPv6 addresses must be surrounded in square brackets, as in the

5205N/A following example:</p>

5205N/A

5205N/A <example>

5205N/A Listen [fe80::a00:20ff:fea7:ccea]:80

5205N/A </example>

5205N/A </section>

5205N/A

5205N/A <section id="ipv6">

5205N/A <title>Special IPv6 Considerations</title>

5205N/A

6226N/A <p>A growing number of platforms implement IPv6, and APR supports

6226N/A IPv6 on most of these platforms, allowing Apache to allocate IPv6

6221N/A sockets and handle requests which were sent over IPv6.</p>

5205N/A

5205N/A <p>One complicating factor for Apache administrators is whether or

5205N/A not an IPv6 socket can handle both IPv4 connections and IPv6

5205N/A connections. Handling IPv4 connections with an IPv6 socket uses

5205N/A IPv4-mapped IPv6 addresses, which are allowed by default on most

5205N/A platforms but are disallowed by default on FreeBSD, NetBSD, and

5205N/A OpenBSD in order to match the system-wide policy on those

5205N/A platforms. But even on systems where it is disallowed by default, a

5205N/A special configure parameter can change this behavior for Apache.</p>

5205N/A

5205N/A <p>On the other hand, on some platforms such as Linux and Tru64 the

5205N/A <strong>only</strong> way to handle both IPv6 and IPv4 is to use

5205N/A mapped addresses. If you want Apache to handle IPv4 and IPv6 connections

5205N/A with a minimum of sockets, which requires using IPv4-mapped IPv6

5205N/A addresses, specify the <code>--enable-v4-mapped</code> <a

5205N/A href="programs/configure.html">configure</a> option.</p>

5205N/A

5205N/A <p><code>--enable-v4-mapped</code> is the default on all platforms but

5205N/A FreeBSD, NetBSD, and OpenBSD, so this is probably how your Apache was

5205N/A built.</p>

<p>If you want Apache to handle IPv4 connections only, regardless of

what your platform and APR will support, specify an IPv4 address on all

<directive module="mpm_common">Listen</directive> directives, as in the

following examples:</p>

<example>

Listen 0.0.0.0:80<br />

Listen 192.170.2.1:80

</example>

<p>If your platform supports it and you want Apache to handle IPv4 and

IPv6 connections on separate sockets (i.e., to disable IPv4-mapped

addresses), specify the <code>--disable-v4-mapped</code> <a

href="programs/configure.html">configure</a> option.

<code>--disable-v4-mapped</code> is the default on FreeBSD,

NetBSD, and OpenBSD.</p>

</section>

<section id="virtualhost">

<title>How This Works With Virtual Hosts</title>

<p> <directive

module="mpm_common">Listen</directive> does not implement

Virtual Hosts. It only tells the

main server what addresses and ports to listen to. If no

<directive module="core" type="section">VirtualHost</directive>

directives are used, the server will behave

the same for all accepted requests. However,

<directive module="core" type="section">VirtualHost</directive>

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

<directive module="core" type="section">VirtualHost</directive> section

should be created for a specified address and port to set the

behavior of this virtual host. Note that if the

<directive module="core" type="section">VirtualHost</directive>

is set for an address and port that the

server is not listening to, it cannot be accessed.</p>

</section>

</manualpage>