Apache HTTP Server Version 2.0
Apache HTTP Server Version 2.0
Configuring Apache to listen on specific addresses and ports.
| Related Modules | Related Directives |
|---|---|
When Apache starts, it binds to some port and address on the local machine and waits for incoming requests. By default, it listens to all addresses on the machine. However, it needs to be told to listen on specific ports, or to listen on 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.
The Listen
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 Listen
directive, the server
listens to the given port on all interfaces. 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 on. The
server will respond to requests from any of the listed
addresses and ports.
For example, to make the server accept connections on both port 80 and port 8000, use:
Listen 80
Listen 8000
To make the server accept connections on two specified interfaces and port numbers, use
Listen 192.170.2.1:80
Listen 192.170.2.5:8000
IPv6 addresses must be surrounded in square brackets, as in the following example:
Listen [fe80::a00:20ff:fea7:ccea]:80
When APR supports IPv6, Apache will create IPv6-capable listening sockets by default (i.e., when no IP address is specified on the Listen directive). In other words, when APR supports IPv6,
Listen 80
is equivalent to
Listen [::]:80
When APR does not support IPv6,
Listen 80
is equivalent to
Listen 0.0.0.0:80
On some platforms, such as NetBSD, binding to the IPv6 wildcard address ("::") does not allow Apache to accept connections on IPv4 interfaces. In this situation, multiple Listen directives are required, as shown below:
Listen 0.0.0.0:80
Listen [::]:0
Apache does not currently detect this, so the Listen statements must be edited manually by the administrator.
Listen does not implement Virtual Hosts. It only tells the
main server what addresses and ports to listen to. If no
<VirtualHost>
directives are used, the server will behave
the same for all accepted requests. However,
<VirtualHost>
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
<VirtualHost> section
should be created for a specified address and port to set the
behavior of this virtual host. Note that if the
<VirtualHost>
is set for an address and port that the
server is not listening to, it cannot be accessed.
