Apache/Virtual hosting

Principle

Virtual hosting in Apache allows a single instance of the Apache software to host more than one distinct web site. Since only one instance of Apache can use port 80 on a server at once, without virtual hosting each new web site you hosted would need a new server.

Sites hosted under virtual hosting appear to end users as normal sites in every way; the only difference is that fewer server machines are needed to host them. Virtual hosting is commonly used by high-volume low-price web hosting companies, who give each of their customers a virtual host, with potentially hundreds of customers sharing the same server.

Configuration

To add a virtual host, edit apache2.conf (or httpd.conf). Example:

<VirtualHost MyIP:80>
  ServerAdmin admin@site1.com
  DocumentRoot /home/site1/public_html
  ServerName site1.com
  ServerAlias www.site1.com
</VirtualHost>

<VirtualHost MyIP:80>
  ServerAdmin admin@site2.com
  DocumentRoot /home/site2/public_html
  ServerName site2.com
  ServerAlias www.site2.com
  AccessLog /home/site2/access.log
  ErrorLog /home/site2/error.log
  <Directory /home/site2/public_html>
    AllowOverride All
  </Directory>
</VirtualHost>