DansGuardian is a web content filter. It filters the actual
content of pages based on many methods including phrase matching,
PICS filtering and URL filtering. It does not purely filter
based on a banned list of sites like lesser totally commercial
filters. DansGuardian is designed to be completely flexible and
allows you to tailor the filtering to your exact needs.

Thanks to Eric Hameleers for the use of his own version of this build.

This requires a proxy server; squid is recommended, if only because
it is also available at SlackBuilds.org.