Disabling Loopback Check

Saru Ponnusamy Senior SharePoint Consultant

Mar 01, 2010

When we have external resources or if we want to point to the local resources instead, we can add entries on the hosts file. But, at times while browsing locally on the server that has links to external resources will throw an 401.2 authentication error because of the loopback that is enabled by default.

To avoid this, we need to add a new DWORD on the registry as described below:

Start->Run->Regedit
Navigate to HKEY_LOCAL_MACHINE -> SYSTEM -> CurrentControlSet -> Control -> Lsa
Add a new DWORD, "DisableLoopbackCheck" if it is not already present
Modify the value to 1
Restart the server

Now, the external resources would resolve as expected. Also note that this will also solve the WSS Crawl error (#2436).

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