Adding Trusted Sites in Citrix Presentation Server 4.5 (or XenApp running on Windows 2003)

To add Trusted Sites for users that use Internet Explorer as a published application on a Citrix Server, the best method to use GPO.

1. Move the Citrix server(s) into an OU, if they are not in one already. Ideally the Citrix server will be the only server located in this OU.
2. Create and link a GPO to this new OU.
3. Turn on loopback processing by going to Computer Configuration -> Administrative Templates -> System -> Group Policy and enabling the 'User Group Policy Loopback Processing' option.
4. Add the sites you want by going to Computer Setttings>Adminstrative Templates>windows components>Internet Explorer>internet control panel>security page>trusted sites zone template. Just type the name of the site in and choose level 2 (the number for Trusted Sites) and click Add.

NOTE: I had trouble at first because I was adding multiple versions of the same site (e.g. https://eservices.paychex.com and *.paychex.com). This is a big no-no as they will conflict and neither site will be added. Try to be as general as possible when adding the sites (e.g. *.domain.com) to avoid these conflicts.