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When I try to connect to SQL Server Express on another machine in the corporate network I face "Cannot generate SSPI context". My machine runs Windows XP and that machine runs Windows 2003 and I don't know much about how the network is structured and what equipment is used where.

I googled and found this article that describes some weird case that it calls "DNS Poisoning". I started nslookup on my machine and results seem pretty much as described in the article:

Address: A.B.C.D
Name: computer_1
Address: A.B.C.D

so there's some computer_1 resolving into the same IP address and I guess that's the problem. Now how do I resolve it? How do I make local DNS server forget the extra entry?

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up vote 2 down vote accepted

First narrow down the cause, then you can work on the best solution.

This may not be malicious, but rather just two machines overlapping each other.

See if you can access both machines and see if they use the same IP. One of them should have an Event Viewer entry for the duplicate IP. Simply use ipconfig on both machines to make sure there aren't duplicate IPs.

On the network adapter advanced settings you can turn off "Register this connection's address in DNS". That will prevent a machine from auto adding its DNS name for each of its assigned IP. And you can also delete the extra record on your DNS server.

However, these are just the affects and not the cause. Somehow between the two machines, either the machine name or the IP is duplicated, so find that and you should be able to correct it.

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