ISA Firewall Quick Tip : Keyword Filtering With ISA Server 2006

ISA Firewall Quick Tip : Keyword Filtering With ISA Server 2006



December 07, 2007
Last Updated : December 07, 2007

Lots of ISA Server Administrators look for a way or an add-on to filter URLs based on the keyword that users try to surf to, or search for in search engines.
On Daily basis, as an ISA Server admin, you will notice that your users are always trying to find new sites related to Sex, or for example Proxy sites to bypass your ISA Server, well in this article, I will show you how to create Keyword Filtering with ISA Server 2004 / 2006


  Before we go on, be informed that the following procedure only applies on Allow Rules  , as you already know, there is no
  Configure HTTP with a Deny Rule

  1. Right click the Allow HTTP rule that you want to apply the keyword filtering on > Click on Configure HTTP

  2. Click on the Signature Tab > Click on the Add button to add a new filtering pattern

  3. Specify a name for the new signature , in this example I will call it Sex Keyword

  4. In the Description Textbox, enter a brief description about the purpose of this signature

  5. In the Search In, choose Request URL

  6. Inside the Signature TextArea box, enter the Keyword that you wish to block, in this example will type sex > Click OK > OK

  7. now lets repeat steps from 1 - 6, but this time for another signature, which is proxy for example

  8. After you have repeated steps from 1 to 6, the created signature will look like this :

  9. So in total now we have two signatures created on the Allow rule, as shown in the following image

  10. Do not forget to click the Apply button

  11. Now lets try our Signatures, open your browser and try to surf to and check what is the result, also go to and in the search box, enter the word sex and check the result ..... Cool right ?

    How about if you tried to go to any site that has the word proxy in it, for example , and even going to any search engine and tried to search for a proxy lists sites, or sites that bypass proxy, and tried to search with the word proxy..... Yah now its more clear how this method is a life saver.

Being able to accomplish simple tasks without the need to purchase a 3rd party application is one of the preferred methods for any ISA Server Administrator. Key Words Filtering is one of the highly requests for most ISA Server administrators.