Telnet session hangs/timeout question?

[Tman45]

Is it possible that telnet sessions are hanging on our devices? We have some nmap scans going on and word has it that it doesn't kill cleanly and we have seen some cards reboot due to 'excessive telnet connections' per our Nortel vendor. We have devices excluded now, but we wondered if the sessions are hanging for days and possibly causing the issue. Does anyone happen to know the timeout for telnet and it would also be good to know the timeout for TCP heartbeat (I think it is around 300 seconds?).

 

[johnpoole]

how long do you need the telnet sessions to last.. you can extend the time by sending anything to restart the idle sesion timers to restart.. the problem with hanging is when you just in the monitor mode..

i haven't seen the problem with cards rebooting but we only use telnet for shorter task

john poole
bellsouth business
columbia,sc

 

[Tman45]

Thanks John - we really want the sessions to end cleanly so I really think it is an issue with nmap scanner. We just thought that these are trying to open many many telnet scans and if they hang open long enough than maybe it is the culprit that has caused our card reboots in the last week. Our system has been pretty clean but we are going through a PCI audit so they are scanning IPs. This is really more of a network question, but it is Nortel CS1000 5.0 PBX related It could be that we are losing TCP heartbeat due to too much congestion ...