Symantec Premium AntiSpam requires the ability to communicate by HTTPS (Port 443). If your connection uses an HTTP proxy, manually register the service so that spam rules can be automatically downloaded from Symantec. To register Symantec Premium AntiSpam through an ISA server that is filtering traffic for your Exchange server, do one of the following:

• If the ISA server is installed on the same computer as the Exchange server, create a Host-based protocol rule. This rule allows "Any Request" for the HTTPS protocol and HTTPS server protocols.

• If the ISA server is installed on a different computer from the Exchange server, create a Host-based protocol rule. This rule specifically allows traffic for the IP address of the Exchange server for the HTTPS protocol and HTTPS server protocols.