Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I am unable to access the local machine through a CNAME alias and receive an "Access denied" error after upgrading to Service Pack 1 of Windows Server 2003.

share|improve this question

This is caused by the "loopback check" security enhancement introduced in Service Pack 1 for Windows Server 2003.

This security feature prevents access to the local server through its fully qualified domain name or CNAME alias, and is enabled by default.

This feature can be disabled by setting the following registry DWORD to 1:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\DisableLoopbackCheck

A server reboot will be required for this change to take effect.

Note that disabling this feature will expose your server to man-in-the-middle NTLM attacks, which this feature is intended to prevent.

More information about this problem is available from MSDN KB926642.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.