This is one of my many posts about FQDN. Most people who followed the guides about setting up SSRS, WSS and TFS in FQDN environment, complained they have to log on each time when the connect to their sites. These sites are still intranet sites, but IE thinks otherwise. IE qualifies any FQDN as an Internet site. If you want to log on automatically to the Local intranet site, you can add the site to trusted sites of the Local intranet. Keep in mind if you changed the level or deselect the "Automatic logon only in Intranet zone" option this workaround won't work.
Open Intranet Options and select the Security Tab. After doing so select Local intranet and click the Sites button.
When the following display appears, select the Advanced button.
These simple steps help you to configure your Internet Explorer so you don't have to log on every time you want to access your portal.