Sunday, May 24, 2009

Cybercafe Pro Client Maxing out 10 Session limit

I had an issue with the cybercafe pro client using up all 10 sessions on the computer running the cybercafe pro server. Whenever a user logs into a workstation it would create a continuous SMB session to the cyber cafe pro server machine. Windows XP Professional only allows 10 at once, this meant if more then 10 users were logged in on an internet machine, no one could use SMB session information through the Server service such as printing. When you kill sessions under computer management they automatically reconnect. See how the idol time is 0 for all sessions of current logged in users?

After installing microsoft network monitor on the client machine, I logged on using a CCP user account, opened network monitor and identified it spamming the CCP server running on

With a bit of research I identified that these microsoft remote procedure calls were related to printing.

opnum0x45 is RpcOpenPrinterEx()
optnum0x4 is RpcEnumJobs()
optnum0x1D is RpcClosePrinter()

In our case we had thousands of optnum0x4 protocol requests hammering the CCP server machine. As soon as 10 users are logged in, it hit the session limit and no one was able to print. I knew it was an issue with CCP because it only started when a user logged in. Also I knew it was printing as the protocol requests were printing related. The cause of the problem turned out to be print monitor module incorporated into CCP causing the ridiculous amount of network spam and using up all the sessions!!!

After un-ticking the box it resolved the problem.

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