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I have an ASP.Net 4.0 application hosted using IIS 6.0 on Windows Server 2003 server. The application is using integrated authentication i.e. Active Directory. Using the same login, i can access the application from the net using a username of DOMAIN\user plus password.

However the app wont authenticate when i RDP into the server and pop a browser open and try to hit the app. Initially i tried using a different dns mapping i.e. a 192.168.x.x mapping in the servers DNS for local users (no reason to go out on the net right) but that wouldn't work so then i used a "proper" internet ip and it still doesn't work.

It is hitting the site either way, as I'm getting an authentication dialog (windows generated) but it will not accept the login.

Any ideas?? Thanks.


As per Tristans accepted answer, it appears to be a LoopBackCheck which I reolved with this powershell command:

New-ItemProperty HKLM:\System\CurrentControlSet\Control\Lsa -Name "DisableLoopbackCheck" -Value "1" -PropertyType dword
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up vote 2 down vote accepted

I'd start with DisableLoopBackCheck and related registry entries, if this is only a server-console thing.

Also, ensure IE Enhanced Security Configuration isn't turned on (Add/Remove Programs for Windows Server 2003).

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Great thanks. It also solved a similar problem I was having with RDPing into one machine and then from that machine RDPing again. – rism Feb 13 '12 at 20:00

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