SharePoint disable loopback check | Specify Host Names

A number of errors related to authentication failure are reported with SharePoint 20xx

You can try disable loopback check  or Specify host names based on how much you can compromise on security front.

Method 1: Specify host names (Preferred method if NTLM authentication is desired)

To specify the host names that are mapped to the loopback address and can connect to Web sites on your computer, follow these steps:

1. Set the

DisableStrictNameChecking
registry entry to 1.

2. Click Start, click Run, type regedit, and then click OK.

3. In Registry Editor, locate and then click the following registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\MSV1_0
4. Right-click MSV1_0, point to New, and then click Multi-String Value.
5. Type BackConnectionHostNames, and then press ENTER.
6. Right-click BackConnectionHostNames, and then click Modify.
7. In the Value data box, type the host name or the host names for the sites that are on the local computer, and then click OK.
8. Quit Registry Editor, and then restart the IISAdmin service.

 
Method 2: Disable the loopback check (less-recommended method)

The second method is to disable the loopback check by setting the DisableLoopbackCheck registry key.

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

                                                 or
$regKeyPath = "HKLM:\System\CurrentControlSet\Control\Lsa"
$key = "DisableLoopbackCheck"
New-ItemProperty -Path $regKeyPath -Name $key -Value "1" -PropertyType dword

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