There is often a need to prevent users from accessing certain sites, or types of site.

For home use, we recommend using a router with DNS filtering, such as the Asus RT-N66U, in conjunction with the free OpenDNS content filtering service.

However, if you need something for commercial purposes or the capability to define complex filters of your own, then we recommend the combination of Squid and Privoxy.

 

The Privoxy user manual describes how to do this here.