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Weird MSLOGON authentication problem

Should you have problems with the MS logon plugin, here's the place to look for help or report issues
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mfo2
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Posts: 20
Joined: 2004-09-02 14:48

Weird MSLOGON authentication problem

Post by mfo2 »

Hi Marscha,

Starting today, UltraVNC on all my computers in the Active Directory domain won't accept to authenticate domain accounts which are also local administrators of these computers. The same domain accounts are still indeed administrators of the computers because I can list the contents of the c$ remotely.
Using the local administrator account and password MSLOGON authentication works.
Using a domain account which belongs to a group declared in the MSLOGON configuration also works.
I'm using the "old" MSLOGON, not the new one.

What could explain a so sudden failure ? Friday the 13th ?
I'm not aware of any change in the AD domain.
I'm using various UltraVNC releases ranging from RC20 to RC205.

I'll try the new MSLOGON to see if it work better than the old one.

Marc
Last edited by mfo2 on 2005-05-13 08:55, edited 1 time in total.
Marscha
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Former moderator
Posts: 464
Joined: 2004-05-14 06:48

Post by Marscha »

With MS-Logon I you can use testauth.exe and see what's happening.
For Win NT/2000/XP/2003 you could use MS-Logon II.

If the problem still remains, check local policy or Group Policy.
Changing some settings can produce very strange effects.
mfo2
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Posts: 20
Joined: 2004-09-02 14:48

Post by mfo2 »

Thank you for your quick answer.
I've got a problem with the new mslogon, it doesn't work on some hardened computers where I remove everyone from the "Access this computer from the network" right.
I just did the test and the new mslogon works where the old one doesn't.
With old mslogon, on a W2K computer with VNC running aas a service, which auth dll should accept the authentication when using a domain account which is local admin of the computer ?
Nothing changed in the GPO or Local Policies between yesterday and today. Still I'm investigating if something else changed.

Marc
mfo2
8
8
Posts: 20
Joined: 2004-09-02 14:48

Post by mfo2 »

Ok I found what was wrong ! The PDC Emulator of the AD domain was in a kind of coma. After reviving it authentications to UltraVNC work again.
So old mslogon relies on PDC Emulator whereas new mslogon doesn't. Wish I could use the new one, it's soooo much faster !!!

Thanks again Marscha and sorry for calling you Mischa (edited my first post), my memory failed me.

Marc
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