mod_usertrack
mod_usertrack is used to generate a cookie for each user session—for
example, to track the user’s click stream within your web tree. You must
enable a custom log that logs this cookie into a log file.
mod_vhost_alias
mod_vhost_alias supports dynamically configured mass virtual hosting,
which is useful for Internet service providers (ISPs) with many virtual hosts.
However, for the average user, Apache’s ordinary virtual hosting support
should be sufficient.
There are two ways to host virtual hosts on an Apache server. You can have
one IP address with multiple CNAMEs, or you can have multiple IP addresses
with one name per address. Apache has different sets of directives to handle
each of these options. (You learn more about virtual hosting in Apache in the
next section of this chapter.)
Again, the available options and features for Apache modules are too
numerous to describe completely in this chapter. You can find complete
information about the Apache modules in the online documentation for the
server included with Ubuntu or at the Apache Project’s website.
Virtual Hosting
One of the most popular services to provide with a web server is to host a
virtual domain. Also known as a virtual host, a virtual domain is a complete
website with its own domain name, as if it were a standalone machine, but it’s
hosted on the same machine as other websites. Apache implements this
capability in a simple way, with directives in the apache2.conf
configuration file.
Apache now can dynamically host virtual servers by using the
mod_vhost_alias module you read about in the preceding section of the
chapter. The module is primarily intended for ISPs and similar large sites that
host a large number of virtual sites. This module is for more advanced users
and is therefore beyond the scope of this introductory chapter. This section
concentrates on the traditional ways of hosting virtual servers.