Harmjan Greving’s Blog

A litle time ago I created a new SharePoint 2010 Web Application. For the hostheader I typed in custom name: intranet. At the root I created a team site. When I tried to access the site collection on http://intranet, I got a HTTP 401.1 - Unauthorized.

This is because Windows Server 2008 and 2003 have a Local Loopback feature turned on by default. You can turn this feature off in the registry:

1. Click Start, click Run, type regedit, and then click OK.
2. In Registry Editor, locate and then click the following registry key:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
3. Right-click Lsa, point to New, and then click DWORD Value.
4. Type DisableLoopbackCheck, and then press ENTER.
5. Right-click DisableLoopbackCheck, and then click Modify.
6. In the Value data box, type 1, and then click OK.
7. Quit Registry Editor, and then restart your computer.

Read more about it in the following Microsoft’s knowledge base article:
http://support.microsoft.com/kb/896861