Ive found this very handy .. recently, I was working on a server and we were trying to access the local SharePoint site http: // 127.0.0.1 or http: // nameoflocalserver/pages/default. aspx and I was constantly prompted for the username and password. in SharePoint 2010 it can really annoy you by not accepting your Username Password credentials in the popup window.
Its a 'feature 'on the server that you need to disable as a workaround ..
You wowould need to create a DWORD registry key in the registry calledDisableloopbackcheckAnd set it to 1.
Follow these steps:
Click Start, click Run, TypeRegedit, And then click OK
In Registry Editor, locate and then click the following registry key:HKEY_LOCAL_MACHINE/system/CurrentControlSet/control/LSA
Right-click LSA, point to new, and then clickDWORDValue.
TypeDisableloopbackcheck, And then press Enter.
Right-click disableloopbackcheck, and then clickModify.
In the value data box, type1And then click OK.
Quit Registry Editor, and thenRestartYour computer.
For more information about this, click the following article number to view the article in the Microsoft Knowledge Base: 281308 (http://support.microsoft.com/kb/281308) connecting to SMB share on a Windows 2000-based computer or a Windows Server 2003-based computer may not work with an alias name.
Original article address:
http://www.jeremytaylor.net/2010/05/24/sharepoint-disable-loopback-check-disableloopbackcheck-dword-in-registry/