There are a few issues you might encounter when installing or configuring ISA Server 2004 on SBS 2004. Here are some of the more common issues:
For the most current information and issues, search for ISA Server 2004 issues at http://support.microsoft.com.
You're prompted to uninstall ISA Server manually because IISAdmin cannot be shut down. In this case, don't uninstall ISA Server 2000 manually, or you'll have to recreate all of your settings. Instead, temporarily disable the IIS Admin Service (also known as IISAdmin) from the Services console, reboot the server, and then restart the installation.
During the installation, you lose connectivity to the server. You're connected remotely. Log into the console at the server itself.
The Configure E-Mail and Internet Connection Wizard fails. You've changed the name of the default SBS Internet Users group. Change it back to SBS Internet Users.
Miscellaneous failures are recorded in the log files. You're not logged into the server with the built-in Administrator account. Log on with the default Administrator account and restart the installation.
After applying Service Pack 1, you might not be able connect to Exchange from Outlook 2003. Changes to the Remote Procedure Call (RPC) filter cause this problem. To resolve the issue, you can either disable the RPC filter (not recommended), or install the Microsoft Internet Security and Acceleration (ISA) Server 2004 Standard Edition RPC Filter Blocks Outlook Traffic from Computers Running Windows Server 2003 Service Pack 1 (SP1) hotfix on your ISA Server 2004 computer from http://go.microsoft.com/fwlink/?LinkID=47520.
If your SBS computer is performing CPU-intensive operations, you might receive a Service Not Responding error with the following detailed description: "Due to an unexpected error, the service fwsrv stopped responding to all requests. Try to stop the service or kill the corresponding process if it does not respond, and start it again. Check the Event Viewer for related error messages."
First, check to ensure that the Fwsrv service is started by opening the Services console from the Administrative Tools folder on the SBS 2003 computer and verify that the Microsoft Firewall service shows a status of Started.
If it is, you can safely ignore the error message, as explained in the article, "You Receive A False Positive Firewall Service Error Message on your ISA Server 2004 Computer," at http://support.microsoft.com/kb/840180.
You might receive an error stating that a Web publishing rule is invalid. Delete the ISA22 rule if you published your http://CompanyWeb site using the article "How to Publish http://Companyweb to the Internet by Using ISA Server 2000 on a Server That Is Running Windows Small Business Server 2003, Premium Edition," at http://support.microsoft.com/kb/838304.