Our organisation officially only supports Windows XP and IE6. I do like progress, so I installed Windows 7 anyway. Most of our internal applications work fine, but whenever I need to go through our proxy server (when the application is not hosted on our corporate network) I run into problems. The proxy uses integrated authentication using your domain credentials. And this doesn't work.

When I use Windows XP (even with IE8) it pops-up a dialog for my username and password and after that it just works. From Windows 7 I get the same dialog, but the sever won't accept my credentials (which are good and valid). My guess is that NTLM authentication changed between Windows XP and Windows 7 and does not work for the ISA server our corporate network uses (no idea which version). Big assumption on my part here: the authentication process uses NTLM. I'm not 100% sure of that, but I thought that was the standard way of doing that.

Does anyone know of a way to adjust settings on Windows 7 to make its NTLM more "Windows XP"-like?


Try changing these registry keys with regedit:

    DWORD  DomainCompatibilityMode = 1
    DWORD  DNSNameResolutionRequired = 0

    DWORD  RequireSignOrSeal = 0
    DWORD  RequireStrongKey = 0
  • 1
    In the Netlogon parameters, there was a "RequireSignOrSeal", is that what you meant? – Jeroen-bart Engelen Jun 21 '10 at 14:38
  • It worked like a charm (and it's RequireSignOrSeal allright). Thanks! – Jeroen-bart Engelen Jun 21 '10 at 14:45
  • Yeah, typo, it should be "RequireSignOrSeal" – Chris S Jun 21 '10 at 14:53

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