1<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 2 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3 4<html xmlns="http://www.w3.org/1999/xhtml"> 5 <head> 6 <meta name="generator" content="HTML Tidy, see www.w3.org" /> 7 8 <title>Apache IP-based Virtual Host Support</title> 9 </head> 10 <!-- Background white, links blue (unvisited), navy (visited), red (active) --> 11 12 <body bgcolor="#FFFFFF" text="#000000" link="#0000FF" 13 vlink="#000080" alink="#FF0000"> 14 <div align="CENTER"> 15 <img src="../images/sub.gif" alt="[APACHE DOCUMENTATION]" /> 16 17 <h3>Apache HTTP Server Version 1.3</h3> 18 </div> 19 20 21 <h1 align="CENTER">Apache IP-based Virtual Host Support</h1> 22 <strong>See also:</strong> <a href="name-based.html">Name-based 23 Virtual Hosts Support</a> 24 <hr /> 25 26 <h2>System requirements</h2> 27 As the term <cite>IP-based</cite> indicates, the server 28 <strong>must have a different IP address for each IP-based 29 virtual host</strong>. This can be achieved by the machine 30 having several physical network connections, or by use of 31 virtual interfaces which are supported by most modern operating 32 systems (see system documentation for details, these are 33 frequently called "ip aliases", and the "ifconfig" command is 34 most commonly used to set them up). 35 36 <h2>How to set up Apache</h2> 37 There are two ways of configuring apache to support multiple 38 hosts. Either by running a separate httpd daemon for each 39 hostname, or by running a single daemon which supports all the 40 virtual hosts. 41 42 <p>Use multiple daemons when:</p> 43 44 <ul> 45 <li>There are security partitioning issues, such as company1 46 does not want anyone at company2 to be able to read their 47 data except via the web. In this case you would need two 48 daemons, each running with different <a 49 href="../mod/core.html#user">User</a>, <a 50 href="../mod/core.html#group">Group</a>, <a 51 href="../mod/core.html#listen">Listen</a>, and <a 52 href="../mod/core.html#serverroot">ServerRoot</a> 53 settings.</li> 54 55 <li>You can afford the memory and <a 56 href="../misc/descriptors.html">file descriptor 57 requirements</a> of listening to every IP alias on the 58 machine. It's only possible to <a 59 href="../mod/core.html#listen">Listen</a> to the "wildcard" 60 address, or to specific addresses. So if you have a need to 61 listen to a specific address for whatever reason, then you 62 will need to listen to all specific addresses. (Although one 63 httpd could listen to N-1 of the addresses, and another could 64 listen to the remaining address.)</li> 65 </ul> 66 Use a single daemon when: 67 68 <ul> 69 <li>Sharing of the httpd configuration between virtual hosts 70 is acceptable.</li> 71 72 <li>The machine services a large number of requests, and so 73 the performance loss in running separate daemons may be 74 significant.</li> 75 </ul> 76 77 <h2>Setting up multiple daemons</h2> 78 Create a separate httpd installation for each virtual host. For 79 each installation, use the <a 80 href="../mod/core.html#listen">Listen</a> directive in the 81 configuration file to select which IP address (or virtual host) 82 that daemon services. e.g. 83<pre> 84 Listen www.smallco.com:80 85</pre> 86 It is recommended that you use an IP address instead of a 87 hostname (see <a href="../dns-caveats.html">DNS caveats</a>). 88 89 <h2>Setting up a single daemon with virtual hosts</h2> 90 For this case, a single httpd will service requests for the 91 main server and all the virtual hosts. The <a 92 href="../mod/core.html#virtualhost">VirtualHost</a> directive 93 in the configuration file is used to set the values of <a 94 href="../mod/core.html#serveradmin">ServerAdmin</a>, <a 95 href="../mod/core.html#servername">ServerName</a>, <a 96 href="../mod/core.html#documentroot">DocumentRoot</a>, <a 97 href="../mod/core.html#errorlog">ErrorLog</a> and <a 98 href="../mod/mod_log_config.html#transferlog">TransferLog</a> 99 or <a href="../mod/mod_log_config.html#customlog">CustomLog</a> 100 configuration directives to different values for each virtual 101 host. e.g. 102<pre> 103 <VirtualHost www.smallco.com> 104 ServerAdmin webmaster@mail.smallco.com 105 DocumentRoot /groups/smallco/www 106 ServerName www.smallco.com 107 ErrorLog /groups/smallco/logs/error_log 108 TransferLog /groups/smallco/logs/access_log 109 </VirtualHost> 110 111 <VirtualHost www.baygroup.org> 112 ServerAdmin webmaster@mail.baygroup.org 113 DocumentRoot /groups/baygroup/www 114 ServerName www.baygroup.org 115 ErrorLog /groups/baygroup/logs/error_log 116 TransferLog /groups/baygroup/logs/access_log 117 </VirtualHost> 118</pre> 119 It is recommended that you use an IP address instead of a 120 hostname (see <a href="../dns-caveats.html">DNS caveats</a>). 121 122 <p>Almost <strong>any</strong> configuration directive can be 123 put in the VirtualHost directive, with the exception of 124 directives that control process creation and a few other 125 directives. To find out if a directive can be used in the 126 VirtualHost directive, check the <a 127 href="../mod/directive-dict.html#Context">Context</a> using the 128 <a href="../mod/directives.html">directive index</a>.</p> 129 130 <p><a href="../mod/core.html#user">User</a> and <a 131 href="../mod/core.html#group">Group</a> may be used inside a 132 VirtualHost directive if the <a href="../suexec.html">suEXEC 133 wrapper</a> is used.</p> 134 135 <p><em>SECURITY:</em> When specifying where to write log files, 136 be aware of some security risks which are present if anyone 137 other than the user that starts Apache has write access to the 138 directory where they are written. See the <a 139 href="../misc/security_tips.html">security tips</a> document 140 for details.</p> 141 <hr /> 142 143 <h3 align="CENTER">Apache HTTP Server Version 1.3</h3> 144 <a href="./"><img src="../images/index.gif" alt="Index" /></a> 145 <a href="../"><img src="../images/home.gif" alt="Home" /></a> 146 147 </body> 148</html> 149 150
