The term Virtual Host refers to the practice of
running more than one web site (such as
company1.example.com and company2.example.com)
on a single machine. Virtual hosts can be "IP-based", meaning that you have a
different IP address for every web site, or "name-based", meaning that you have
multiple names running on each IP address. The fact that they
are running on the same physical server is not apparent to the
end user.
Apache was one of the first servers to support IP-based virtual hosts right out of the box. Versions 1.1 and later of Apache support both IP-based and name-based virtual hosts (vhosts). The latter variant of virtual hosts is sometimes also called host-based or non-IP virtual hosts.
Below is a list of documentation pages which explain all details of virtual host support in Apache HTTP Server:
If you are trying to debug your virtual host configuration, you
may find the Apache -S command line switch
useful. That is, type the following command:
This command will dump out a description of how Apache parsed
the configuration file. Careful examination of the IP addresses and
server names may help uncover configuration mistakes. (See
the docs for the