I am running multiple TS servers of Linux version 2.0.18.25. I have one client who every time he gets about 50 users on his server (max users is set to 70), it locks up. Nothing in the log indicates that there is any problem and all the processes are still alive. If you try to join, you get a server not responding message. When it locks up, the only way to fix it is to stop and restart the server. If you mess with it with the web admin thing while it is locked up, you can corrupt the server.db file and then you can't even restart the server.
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