Apache HTTP Server Version 2.0

Apache IP-based Virtual Host Support

System requirements

How to set up Apache

Use multiple daemons when:

• There are security partitioning issues, such as company1 does not want anyone at company2 to be able to read their data except via the web. In this case you would need two daemons, each running with different User, Group, Listen, and ServerRoot settings.
• You can afford the memory and file descriptor requirements of listening to every IP alias on the machine. It's only possible to Listen to the "wildcard" address, or to specific addresses. So if you have a need to listen to HTTP/1.1 200 OK Date: Mon, 07 Jul 2025 08:39:35 GMT Server: Apache/2.0.42 (Win32) PHP/5.2.10 Accept-Ranges: bytes Content-Length: 6301 Keep-Alive: timeout=15, max=100 Connection: Keep-Alive Content-Type: text/html; charset=ISO-8859-1
  

  Apache HTTP Server Version 2.0

  Apache IP-based Virtual Host Support

  See also: Name-based Virtual Hosts Support

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  System requirements

  As the term IP-based indicates, the server must have a different IP address for each IP-based virtual host. This can be achieved by the machine having several physical network connections, or by use of virtual interfaces which are supported by most modern operating systems (see system documentation for details, these are frequently called "ip aliases", and the "ifconfig" command is most commonly used to set them up).

  How to set up Apache

  There are two ways of configuring apache to support multiple hosts. Either by running a separate httpd daemon for each hostname, or by running a single daemon which supports all the virtual hosts.

  Use multiple daemons when:

  • There are security partitioning issues, such as company1 does not want anyone at company2 to be able to read their data except via the web. In this case you would need two daemons, each running with different User, Group, Listen, and ServerRoot settings.
  • You can afford the memory and file descriptor requirements of listening to every IP alias on the machine. It's only possible to Listen to the "wildcard" address, or to specific addresses. So if you have a need to listen to a specific address for whatever reason, then you will need to listen to all specific addresses. (Although one httpd could listen to N-1 of the addresses, and another could listen to the remaining address.)
  Use a single daemon when:
  • Sharing of the httpd configuration between virtual hosts is acceptable.
  • The machine services a large number of requests, and so the performance loss in running separate daemons may be significant.

  Setting up multiple daemons

  Create a separate httpd installation for each virtual host. For each installation, use the Listen directive in the configuration file to select which IP address (or virtual host) that daemon services. e.g.

      Listen www.smallco.com:80
  

  It is recommended that you use an IP address instead o