While creating a test SharePoint 2010 Farm I have installed all the software, solution, attached content database and wanted to see the result being on one of front-end servers, sp10wfe1. Test portal URL is http://sp10. So I entered URL in browser http://sp10 and wanted to see a site. Browser asked me about login and password, I entered them once, twice. On the third try it just show empty window.

I know I didn’t enter 3 time wrong password.

After some time of troubleshooting I found an article on Microsoft site about LoopBack. According to it, you can’t open SharePoint site from web front end machine. Of course, it’s not very necessary in production SharePoint farm, but on test lab or developer environments it’s very useful.

It’s rather easy to disable loopback. You need to add only one record to registry.

In node HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa you need to create a new DWORD value. It must be named as DisableLoopbackCheck, and it’s value is 1.

You can easily do it with powershell:

New-ItemProperty HKLM:\System\CurrentControlSet\Control\Lsa -Name "DisableLoopbackCheck" -Value "1" -PropertyType dword