Version 2.2 of the Apache HTTP Server.
When asking questions about virtualhosts, please include the output of the following command: "apache2ctl -S" (or "httpd -S" depending on your OS)
OFF-TOPIC WARNING: Apache version 2.2 reached end-of-life with the final release of version 2.2.34 in July 2017. No further evaluation of security risks will be published for 2.2.x releases, and Apache users should immediately transition to version 2.4.x. Because Apache 2.2 is unsupported, most, if not all, questions regarding Apache 2.2 will be off-topic on ServerFault.
The Apache HTTP Server is a popular Open Source Web server.
This tag should be used for questions specific to version 2.2 of Apache HTTPD. For more general Apache HTTP Server related questions, you should use the Apache2 tag instead.
Apache is very well documented and most functionality is described in detail within this documentation. Specific documentation is available for Version 2.2
If you are asking a question on Server Fault about Virtual Hosts, can you please include the output of either:
# Debian Linux and its derivates
apache2ctl -S
# Most other UNIX/Linux distributions
apachectl -S
# Non UNIX/Linux distributions or if you are unable to find apachectl
httpd -S
Including this will involve in a much faster answer to your question, as no doubt the first thing people will ask for is that output.
For questions about Apache 2.4 please use apache-2.4