Virtual Web Hosting
Virtual web hosting refers to the process of running multiple "virtual" web servers on a single physical host computer. Using this technique, a single computer can host thousands of independent web sites. Commercial web hosting service providers often use this technique to allow better manageability, efficiency and scalability of their service infrastructure.
Most virtual web hosting applications rely on virtual DNS resolution, so that a specific domain name (such as a customer's own registered domain name) may be associated with each independent virtual web server. This can be achieved through either name-based or IP-based virtual web hosting. These techniques are explained below.

What is name-based web hosting?
Name-based web hosting is a technique that can be used when providing virtual web hosting services. Each web site that is hosted on a single machine shares a single public IP address. All HTTP GET requests received by this web server are answered according to the domain name supplied by the requesting client, enabling the web server to differentiate between multiple virtual sites on the one IP address.

What is IP-based web hosting?
IP-based hosting is a technique that can be used when providing virtual web hosting services. Each web site that is hosted on a single machine is given its own separate public IP address. The HTTP GET requests are resolved by using the IP address instead of the name.
Operating system limitations may also limit the maximum number of IP addresses that can be assigned to a single machine, especially if separate log files are used.
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