Tadlock Enterprises » registry http://www.tadlockenterprises.com A specialized west coast firm focused on product and technology vision, planning and execution. Thu, 18 Mar 2010 07:45:03 +0000 http://wordpress.org/?v=2.9.2 en hourly 1 Fix Loopback 401 Errors in Windows Server 2008 http://www.tadlockenterprises.com/2010/02/fix-loopback-401-errors-in-windows-server-2008/ http://www.tadlockenterprises.com/2010/02/fix-loopback-401-errors-in-windows-server-2008/#comments Thu, 25 Feb 2010 08:13:16 +0000 Craig Tadlock http://www.tadlockenterprises.com/?p=446 If you use a loopback address (127.0.0.1) or hosts files on your Windows Server to reference a local IIS web application with Windows Authentication it will probably fail with a 401 error due to a new security constraint. This is often the case if you use a public url for your Sharepoint of TFS server. To resolve this you need to add a registry key…

  1. Open regedit
  2. Open the key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
  3. Create a new DWORD under Lsa named DisableLoopbackCheck
  4. Set its value to 1
  5. Restart the server for good measure

Related Links

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

http://ppalakollu.blogspot.com/2009/04/ie-8-ntlm-authentication-on-windows.html

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