Configure SharePoint – Disable Loopback on SharePoint WFE Servers

 

Overview

I work on a lot of different SharePoint servers and most of the time I don’t have a separate “Client” computer I can use to see how the server is responding.  Many times it will appear that SharePoint is broken because of a loopback issue in IIS.  When you browse the SharePoint site from the web front end server the server will repeatedly ask for authentication until you get a 401.1 error.  The process looks a like this:

Continuous Authentication Boxes:

 

Eventual failure:

 

Fortunately you can disable the loopback check, the process is described in Microsoft KB http://support.microsoft.com/kb/896861.  I recommend performing this on all your SharePoint servers, but at the very least the server you will be using for administration.  My recommendation is use option 2:

 

“Method 2: Disable the loopback check

Follow these steps:

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.”http://support.microsoft.com/kb/896861.