SquidGuard is a URL redirector software, which can be used for content control of websites users can access.
It is written as a plug-in for Squid and uses blacklists to define sites for which access is redirected.
It was originally developed by Pål Baltzersen and Lars Erik Håland, and was implemented and extended by Lars Erik Håland in the 1990s at Tele Danmark InterNordia.
[2][failed verification] New features in version 1.4 included optional authentication via a MySQL database.
[7] The url filtering capabilities of SquidGuard depend largely on the quality of the Blacklists used with it.