CITA 310 Section 5

1. CITA 310 Section 5 Virtual Hosts and Virtual Directories (Selected Topics from Textbook Chapter 6)

2. 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.

3. 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.

4. 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.

5. 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.

6. 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.

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

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

9. Name-Based Virtual Host Example • NameVirtualHost 127.0.0.1:80 <VirtualHost 127.0.0.1:80> ServerName localhostDocumentRoot htdocs</VirtualHost> <VirtualHost 127.0.0.1:80>ServerName test.cita.eduDocumentRoot htdocs/test</VirtualHost>

10. 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.

11. 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 between Allow from all </Directory>

12. 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 case-sensitive path beginning with a slash. A relative path is not allowed. • Example: Redirect /google http://www.google.com