Microsoft 2004 Manuel D’Utilisation

Use HTTP Policy to Prevent Access to Suspect Web 
Sites 

You can block access to Web sites based on virtually any component of the HTTP 
communication using ISA Server 2004 HTTP policy. For example, you might want to prevent 
access to all Web sites that contain a reference to the popular file-sharing application, Kaaza. 
This file-sharing program can present a risk to network security because the files downloaded 
via this application can contain viruses, worms and copyrighted material. 

In the following walkthrough, you will configure the HTTP policy for the Administrator 
Internet Access and Limited Access Web Users rules to block all Web connections to sites 
that contain the string “Kaaza” in them. While this example uses a blunt approach to blocking 
Kaaza-related sites, it does demonstrate the power of ISA Server 2004’s deep HTTP 
inspection mechanisms. 

Perform the following steps to prevent users from accessing Kaaza-related sites: 

1. In 

the 

Microsoft Internet Security and Acceleration Server 2004 management 

console, click on the Firewall Policy node. 

2.  Right click on the Administrator Internet Access rule and click Configure HTTP. 

 

3. In 

the 

Configure HTTP policy for rule dialog box, click on the Signatures tab. 

4. On 

the 

Signatures tab, click on the Add button. 

5. In 

the 

Signature dialog box, enter a name for the signature in the Name text box. In this 

example we will enter Kaaza URL. Select the Request URL entry in the Search in list. 
Enter the string kaaza in the Signature text box. Click OK. 

ISA Server 2004 Configuration Guide 153