0N/A<?
xml version="1.0" encoding="UTF-8" ?>
0N/A<!-- $LastChangedRevision$ --> 0N/A Licensed to the Apache Software Foundation (ASF) under one or more 0N/A contributor license agreements. See the NOTICE file distributed with 0N/A this work for additional information regarding copyright ownership. 0N/A The ASF licenses this file to You under the Apache License, Version 2.0 0N/A (the "License"); you may not use this file except in compliance with 0N/A the License. You may obtain a copy of the License at 0N/A Unless required by applicable law or agreed to in writing, software 0N/A distributed under the License is distributed on an "AS IS" BASIS, 0N/A WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 0N/A See the License for the specific language governing permissions and 0N/A limitations under the License. 0N/A <
title>Binding</
title>
0N/A <
p>Configuring Apache HTTP Server to listen on specific addresses and ports.</
p>
0N/A <
seealso><
a href="vhosts/">Virtual Hosts</
a></
seealso>
0N/A <
section id="overview">
0N/A <
title>Overview</
title>
0N/A <
module>core</
module>
0N/A <
module>mpm_common</
module>
0N/A <
directive module="core" type="section">VirtualHost</
directive>
0N/A <
directive module="mpm_common">Listen</
directive>
0N/A <
p>When httpd starts, it binds to some port and address on
0N/A the local machine and waits for incoming requests. By default,
0N/A it listens to all addresses on the machine. However, it may need to
0N/A be told to listen on specific ports, or only on selected
0N/A addresses, or a combination of both. This is often combined with the
0N/A Virtual Host feature, which determines how httpd responds to
0N/A different IP addresses, hostnames and ports.</
p>
0N/A <
p>The <
directive module="mpm_common">Listen</
directive>
0N/A directive tells the server to accept
0N/A incoming requests only on the specified ports or
0N/A address-and-port combinations. If only a port number is
0N/A specified in the <
directive module="mpm_common">Listen</
directive>
0N/A directive, the server
0N/A listens to the given port on all interfaces. If an IP address
0N/A is given as well as a port, the server will listen on the given
0N/A port and interface. Multiple <
directive 0N/A module="mpm_common">Listen</
directive> directives may be used to
0N/A specify a number of addresses and ports to listen on. The
0N/A server will respond to requests from any of the listed
0N/A addresses and ports.</
p>
0N/A <
p>For example, to make the server accept connections on both
0N/A port 80 and port 8000, on all interfaces, use:</
p>
0N/A <
p>To make the server accept connections on port 80 for one interface,
0N/A and port 8000 on another, use</
p>
0N/A Listen 192.0.2.1:80<
br />
0N/A Listen 192.0.2.5:8000
0N/A <
p>IPv6 addresses must be enclosed in square brackets, as in the
0N/A following example:</
p>
0N/A Listen [2001:db8::a00:20ff:fea7:ccea]:80
0N/A <
title>Special IPv6 Considerations</
title>
0N/A <
p>A growing number of platforms implement IPv6, and
0N/A <
glossary>APR</
glossary> supports IPv6 on most of these platforms,
0N/A allowing httpd to allocate IPv6 sockets, and to handle requests sent
0N/A <
p>One complicating factor for httpd administrators is whether or
0N/A not an IPv6 socket can handle both IPv4 connections and IPv6
0N/A connections. Handling IPv4 connections with an IPv6 socket uses
0N/A IPv4-mapped IPv6 addresses, which are allowed by default on most
0N/A platforms, but are disallowed by default on FreeBSD, NetBSD, and
0N/A OpenBSD, in order to match the system-wide policy on those
0N/A platforms. On systems where it is disallowed by default, a
0N/A special <
program>configure</
program> parameter can change this behavior
0N/A <
p>On the other hand, on some platforms, such as Linux and Tru64, the
0N/A <
strong>only</
strong> way to handle both IPv6 and IPv4 is to use
0N/A mapped addresses. If you want httpd to handle IPv4 and IPv6 connections
0N/A with a minimum of sockets, which requires using IPv4-mapped IPv6
0N/A addresses, specify the <
code>--enable-v4-mapped</
code> <
program>
0N/A configure</
program> option.</
p>
0N/A <
p><
code>--enable-v4-mapped</
code> is the default on all platforms except
0N/A FreeBSD, NetBSD, and OpenBSD, so this is probably how your httpd was
0N/A <
p>If you want httpd to handle IPv4 connections only, regardless of
0N/A what your platform and APR will support, specify an IPv4 address on all
0N/A <
directive module="mpm_common">Listen</
directive> directives, as in the
0N/A following examples:</
p>
0N/A Listen 0.0.0.0:80<
br />
0N/A <
p>If your platform supports it and you want httpd to handle IPv4 and
199N/A IPv6 connections on separate sockets (
i.e., to disable IPv4-mapped
0N/A addresses), specify the <
code>--disable-v4-mapped</
code> <
program>
0N/A configure</
program> option. <
code>--disable-v4-mapped</
code> is the
0N/A default on FreeBSD, NetBSD, and OpenBSD.</
p>
0N/A <
section id="virtualhost">
0N/A <
title>How This Works With Virtual Hosts</
title>
0N/A module="mpm_common">Listen</
directive> directive does not implement
0N/A Virtual Hosts - it only tells the
0N/A main server what addresses and ports to listen on. If no
0N/A <
directive module="core" type="section">VirtualHost</
directive>
0N/A directives are used, the server will behave
0N/A in the same way for all accepted requests. However,
0N/A <
directive module="core" type="section">VirtualHost</
directive>
0N/A can be used to specify a different behavior
0N/A for one or more of the addresses or ports. To implement a
0N/A VirtualHost, the server must first be told to listen to the
0N/A address and port to be used. Then a
0N/A <
directive module="core" type="section">VirtualHost</
directive> section
0N/A should be created for the specified address and port to set the
0N/A behavior of this virtual host. Note that if the
0N/A <
directive module="core" type="section">VirtualHost</
directive>
0N/A is set for an address and port that the
0N/A server is not listening to, it cannot be accessed.</
p>