Content Filters

Background

While proxy servers temporarily cache your internet content for faster network access, content filters can assess web traffic entering your network, and block access to web sites according to pre-determined rules.

Content filters are often installed in conjunction with a proxy server - in small networks they are often running on the same hardware.

Which content filter?

The biggest decision to make when planning an internet content filtering system for your network is whether you want to DIY, or pay for a commercial product, or find a solution somewhere in between.

There are many commercial providers of both filtering software, and dedicated filtering appliances. Some of these are listed below.

The first choice for DIY is Dandguardian. A number of commercial software filtering solutions are also built around the Dansguardian software.

Details of some of the options are listed below:

(I wrote many of the "how-to" notes below quite a while ago while experimenting with options for my own use. That need has now faded and some of the suggested software may have been updated since then, but the notes should still be generally applicable.)

DansGuardian - Home Page

If you would like to setup a local content filter at a school, or you have a broadband connection at home and are interested in setting up a content filter to keep the kids out of trouble, this is the product. Free for non-commercial use.

For Red Hat Linux

Red Hat DansGuardian Installer
- go to Downloads > stable > Red Hat for the RPM
DansGuardian WebMin module
- Use WebMin web interface to administer DansGuardian.

For Mac OS X

If you like to tinker with these things, you can combine Squid and DG, using a WebMin interface....

Software
SquidMan
- a neat OS X Squid installer with a GUI.
Dandguardian Installer
- Mac OS X installer package
WebMin - OSX Package
- Provides a web interface to administer DG.
DansGuardian WebMin module
- Enables Webmin to config DG.

How-to
SquidMan-DansGuardian-WebMin setup notes - OS X 10.2 (pdf - 1.75 Mb)

Note: Something is broken in the latest (2009) Mac OS X implementation of WebMin and the Dansguardian module, causing WebMin to report that "the version you have is not supported" when loading the DG module. For now, maybe try to use older versions of the software.

See also:

Other Mac OSX Info
Mac OS X Squid-Dansguardian Installer
- Installs DansGuardian and Squid, but cannot be easily re-configured for parent proxies, etc.
Webmin installation instructions
- from phpMac - incorporated into Wazza's notes above.

Old Mac OS X Stuff

A really great OS X Installer for Dansguardian was developed by Dave Lopata, but this appears to no longer be available. Dave provided a complete DG/Squid installer, including a neat GUI console for Dansguardian:

Dave Lopata's OSX DG Installer

I still check occasionaly to see if it has returned. It was a great simple-to-setup implementation of caching/filtering software for that old Mac in your storeroom.

Troubleshooting

Dansguardian Unsupported
Some info about configuring Dansguardian so that it can be managed by WebMin.

CensorNet (Linux)

Content filter & firewall - an open-source project built on the Dansguardian filter.

ClarkConnect (Linux)

Includes firewall and security tools, file, print, web, e-mail, proxy, antivirus, antispam, content filtering, VPN servers (Free version for Home use).

getbusi

Aussie web management software. (Commercial)

LightSpeed

Popular commercial Internet security software for K-12 schools.

iSherrif

Commercial filtering tool, suitable for small and large organisations.

SafeSquid (Linux)

Internet Proxy, content filtering web-gateway, Internet Access Manager, Internet Bandwidth use optimiser. Free edition available.

SquidGuard (Linux)

An ultrafast filter, redirector and access controller for Squid. Filters by URL, not the content of pages (unlike DansGuardian). Free, but Unix tech experience essential!

 

See also:

WebSense
iPrism - a content filtering "appliance".