To set the scene, we have just created a WSS 3 site using forms based authentication. Published it through ISA 2004. Browsed to the site and we get this error.
Following Microsoft’s guidance and information on various blogs, it suggetsed to disable the Verify Normalisation and the Block High Bit Characters options in the HTTP filter. We browsed to the rule in question, opened the Properties and selected the Trafic tab. The HTTP and HTTPS protocols are listed, but the Filtering button is disabled.
Things to check to enable this Filtering button are:
- Go to Configuration –> Add-Ins
- Ensure that the Web Proxy Filter is shown and enabled (if you have the option to disable it)
- Select Web Filters and ensure that the HTTP Filter is present and enabled
- Go to Firewall Policy and open the HTTP Protocol Properties
- On the Parameters tab, in the Application Filters panel ensure that Web Proxy Filter is checked.
- Apply your changes.
The Filtering button on the Traffic tab will now be available and the Verify Normalisation and Block High Bit Characters can be disabled.