CITA 310 Section 5

Virtual Hosts and Virtual Directories(Selected Topics fromTextbook Chapter 6)

Virtual Hosts When Apache is configured for

only one Web site or URL, it functions as a single main server.

With virtual hosts, Apache functions as if it were a series of multiple, separate servers, each devoted to a URL.

Configuring Virtual Hosts You configure each virtual host by

adding a VirtualHost container for it in the Apache configuration file.

The opening VirtualHost directive specifies the IP address and an optional port number in which this virtual host should listen.

IP-Based Virtual Hosts Useful for flexibility because if

each host has its own unique IP address, you can easily move the host to a different Web server.

It is getting more expensive to get multiple IP addresses from an ISP.

Port-Based Virtual Hosts Associate each new Web site with

a port above 1023. Because it requires a user to add

the port number, it is not a popular method.

Name-Based Virtual Hosts Multiple host names can be associated

with a single IP address. Getting a single IP address from your

ISP is relatively inexpensive. You can host an almost unlimited

number of hosts with a single IP address.

It is the most common method of hosting.

IP-Based Virtual Host Example <VirtualHost 192.168.0.150>ServerName research.cita.comDocumentRoot htdocs/research</VirtualHost>

Port-Based Virtual Host Example Listen 8080 <VirtualHost 127.0.0.1:8080>DocumentRoot htdocs/test</VirtualHost>

Name-Based Virtual Host Example NameVirtualHost 127.0.0.1:80 <VirtualHost 127.0.0.1:80> ServerName www.cita.comDocumentRoot htdocs</VirtualHost> <VirtualHost 127.0.0.1:80>ServerName test.cita.comDocumentRoot htdocs/test</VirtualHost>

ServerAlias Directive The ServerAlias directive sets the

alternate names for a host, for use with name-based virtual hosts.

The ServerAlias may include wildcards, if appropriate.

Configuring a Virtual Directory in Apache The following associates the virtual

directory called testdir with the location of the directory

Alias /testdir C:/testdir Then it configures the directory<Directory C:/testdir>Order allow,deny <-- no space in betweenAllow from all</Directory>

Redirection The Redirect directive maps an old

URL into a new one by asking the client to re-fetch the resource at the new location.

The old URL is a path beginning with a slash. A relative path is not allowed.

Example: Redirect /google http://www.google.com