What Is Name-based Virtual Hosting?

As seen in the previous sections, IP virtual hosting requires a different IP address for each website. This creates quite a few problems if you need to host a great number of websites or you cannot get or do not want to pay for more than one IP address. An example where this would be the case would be if you wanted to run several personal websites out of your own server at the end of a DSL line.

Name-based virtual hosting takes advantage of the fact that most browsers in widespread use (and almost all recent ones) transmit a Host: header in their HTTP request. This is a requirement of the HTTP/1.1 protocol, but is also present in most implementations of HTTP/1.0. Thus, we can decide which information to present to the user based on data from the HTTP request, rather than on data from the connection itself. This allows several virtual hosts to share the same IP address and port combination.