Setting up multiple Web servers can be a costly endeavor. However, by setting up virtual hosting on webserver can drastically cut costs. In doing so, configuring host multiple Web sites on a single machine, which will afford savings in time, hardware, and IP addresses.
Three types of virtual hosts can be configured on Apache :
An IP-based virtual host looks at the IP address of the requested site and then connects the Apache configuration file to find the location of the content that serves that IP address. This method requires a separate IP address for each host installed on the Apache server. In DNS, each Web site also has its own IP address.
IP-based virtual hosts allow to run multiple Web sites on the same physical hardware. Unlike name-based hosts, however, IP-based virtual hosts generally require that additional IP addresses be assigned to the host. This doesn't necessarily need multiple physical network adapters
A name-based virtual host uses the headers sent from the requesting client to determine which content to send back to the client. This type of virtual hosting arrangement can be supported with a single IP address. In DNS, all Web sites that reside on the particular server share the same IP address.
Setting up the names in DNS is much easier than trying to rely on local hosts files. If you don't control your DNS server and just want to test virtual hosting, set up a DNS such as BIND on your Linux server. If you decide to do this, do it in a lab first so you don’t cause total network confusion by adding unknown DNS servers on the production network.
A port-based virtual host allows the server to take advantage of port redirection. With this type of virtual host, a server can be running hosts on the same IP address on ports 80, 8080, etc.
In addition to using names and IP addresses, Apache can listen for traffic on other TCP ports and serve up content to requests that come in to that port. Port-based virtual servers are often used in conjunction with load-balancing equipment. The load balancers are configured with the DNS name and the TCP port that serves the content. This TCP port matches the Apache virtual server configuration.
Advanatages / Disadvantages :
1. IP based virtual hosting requires, individual IP addresse.
2. Name based virtual hosting cannot be used with SSL
3. For SSL setup is possible only with IP based virtual hosting.
Contents taken from link :
http://articles.techrepublic.com.com/5100-10878_11-5031750.html
Sunday, February 8, 2009
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