I faced a strange issue recently, i have deployed SharePoint 2003 servers for one project and one of the requirements was to open SharePoint site from same server. when i was trying to open site from the same server i was getting authentication prompts and the site was not opening. I have even added the URL entry in the local host file but the issue remains same. After googling i found one Microsoft KB on the same issue which stated that “This issue occurs if you install Microsoft Windows XP Service Pack 2 (SP2) or Microsoft Windows Server 2003 Service Pack 1 (SP1). Windows XP SP2 and Windows Server 2003 SP1 include a loopback check security feature that is designed to help prevent reflection attacks on your computer. Therefore, authentication fails if the FQDN or the custom host header that you use does not match the local computer name.”
In order to fix this we need to disable loopback check on all web server which are facing this behavior. I have applied this fix on my both front-end servers and after restarting both front-end servers the issue solved and i can now open website on same server. Following is the fix i followed.
Following is the KB for this issue;