Filtering home Internet access with Squid


Even if your kids keep to the times that they are allowed to surf the web, you will not want them accessing sites with pornographic or violent content.

To place websites off limits, you just need to add a couple of lines to your Squid configuration file (see Listing 7) then add entries with strings describing the web content you want to block to the /usr/share/squid/blacklist file (see Listing 8); regular expressions [4] are supported.

Finally, type /etc/init.d/squid reload to tell the proxy to parse the blacklist.

Listing 7

Place websites off limits


Listing 8

Block web content


Custom Blacklists

Of course, Squid will let you assign different blacklists to different users. For example, Simon is allowed to browse online auctions, whereas Tanja is still too young for such things. To set this up, just assign the blacklist in Listing 8 as /usr/share/squid/blacklist_tanja.

The example blocks pages that contain the prohibited text. To define more precise filters, you can use regular expressions, but don't rely blindly on the list; it makes far more sense to check at regular intervals to see whether it still has the desired effect. And remember that server and file names do change.


Another approach to filtering, and one that is far more strict, is to use whitelists. If you prefer to restrict Tanja's access to just one or a few sites, a whitelist is probably a good idea. Just add the lines in Listing 9 to your Squid configuration and create a whitelist to match. The syntax is similar to that of the blacklist; however, whitelisting can cause problems when a single website references content from many other locations.

To display the complete page, you would need to list these sites explicitly.

Listing 9

Adding a Whitelist


Buy this article as PDF

Express-Checkout as PDF
Price $2.95
(incl. VAT)

Buy Linux Magazine

Get it on Google Play

US / Canada

Get it on Google Play

UK / Australia

Related content

  • Squid proxy server

    A proxy server provides safer and more efficient surfing. Although commercial proxy solutions are available, all you really need is Linux and an old PC in the attic.

  • Security Lessons – Squid Filtering

    Kurt describes how to use Squid's ACLs and ICAP when you want to limit Internet access, for whatever reason.

  • Squid Bridge

    Caching proxies remember web pages and serve them up locally, saving both money and time. The most intelligent members of this family also remove dangerous content and provide transparent bridging.

  • SafeSquid

    If you are looking for a secure option for home surfing and want to protect your children against questionable web content, you need a filtering proxy. SafeSquid is a commercial proxy tool, but it comes with a free version for private users.

  • Filter Proxy for AD

    You might want to reap the benefits of active directory’s single sign-on for your virus scanning and content filtering. If you also use Squid to handle user access to the internet, you have a front-row seat for “when worlds collide.”

comments powered by Disqus
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters

Support Our Work

Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.

Learn More