Low cost content filtering .. finally!

When I posted back on 8th May "I'm working on it, and I'll report back next week!" I didn't imagine it would take this long, but it did.  Initially my problems were with the scripts which populate a URL set or Domain Set in ISA Server from a text file.  The domains file from the 'Adult' category is 14MB and contains over 850,000 domains (and that's just one category, though it is the largest).

After trying to resolve this (scripts running over 8 hours!) I started looking for some alternatives, and found a script by Rob Bosch, (ISA expert and co-founder of iPremise) which did the trick.

So now we have a very low cost internet filtering option!

The process is this;

1. Subscribe to and download the blacklist from URLBlacklist.com (£36 per year for a small business or school to download once a month, which should be sufficient for most).
2. Uncompress the file (use gzip -d bigblacklist.tar.gz and tar -xf bigblacklist.tar, requires cygwin utils)
3. Create the files BuildXML.vbs, includes.txt, linetemplate.txt and template.xml from the post by Rob
4. Edit the includes.txt file to include the categories you want to blacklist
5. Run BuildXML.vbs
6. Import the resulting blacklist.xml file into a URL Set in ISA Server 2004 and apply the change.

This process all took a fraction of the time taken by the scripts I was using before, and provides you with the best low cost option for content filtering, which is entirely under your control!

If you're looking for an alternative option whilst looking into alternatives I find OpenDNS, which provides a free DNS service with an option to filter sites by category, whitelist sites and blacklist individual domains.  The service is based on the St Bernard iGuard service and their own PhishTank service.  The downside?  If someone on your network types in a URL which isn't found, it will offer up "clearly labeled advertisements alongside organic search results when the domain entered is not valid and not a typo we can fix".  For many, this could be cheap at the price.

For more advice on reducing your IT spend contact richard@rgbartlett.co.uk, or see the website for more details.