Why does authenticating against LDAP with DirectoryEntry intermittently throw COMException (0x8007203A): “The server is not operational”?

Question

If anybody has a similar story, please post details below!

I\'m building an ASP.NET website which needs to support authentication against LDAP.

Answer 1

Although I can't precisely pinpoint the cause of this trouble, it seems to have to have stopped after migrating to a non-clustered server.

There are other odd facts about this bug:

• Restarting the asp.net host process isn't sufficient to fix the trouble. This is odd; you'd expect the OS to forcibly release resources on process death
• Restarting the IIS service doesn't release the resources (the UDP ports). netstat reveals the ports seem free, but all ports opened are actually opened by process #4 - the System process.
• Killing IIS (for instance via the IIS manager) does release the UDP ports, and then authentication works again.

All in all, this looks very much like a driver or kernel issue in win2k3 with clustering enabled, and not a .NET related problem.

So, if anyone else stumbles over a similar problem, check to see if clustering is enabled - it may save you weeks of headaches.