Use the ForceFQHost parameter in the Web Agent ACO or localconfig.conf.
Set ForceFQHost = yes (default: no)
The ForceFQHost parameter ensures the use of fully qualified domain names.This parameter uses DNS services to force the appending of the cookie domain to the host name in a URL request via DNS services and not an Agent.
If the Web Agent receives a request that contains a partial URL, the Web Agent redirects the request back to the same destination resource specified in the original URI. The redirect request uses the fully qualified host name, which the Web Agent determines using the configured domain name system DNS services. Enforcing the use of fully qualified domain names together with the Agent s ability to resolve cookie domains based on incoming host headers helps SiteMinder manage sites that have many domains across a network.