Re: [PLUG] ssh disconnect weirdness

On Nov 25, 2007 11:49 AM, W. Chris Shank <shankwc@acetechgroup.com> wrote:

Dumb question

not really!

Some, when I try to logout of the ssh session it hangs the terminal.

can we get specs on the clients and servers, including the kind of networks they're on and any routers/switches/hubs being used?

Sometimes if I wait a while my client will eventually release it and I'll get back to my local shell. On other servers, if the connection is inactive for more than I few minutes the session is closed.

are they all using the same distro?

can you post:

~/.ssh/config (if it exists)
/etc/ssh/ssh_config

from any clients, and

/etc/ssh/sshd_config

from any servers?

what i think is going on is aside from a possible hardware/network issue, you have different keepalives et. al. set on the servers and/or different sending of keepalives et. al. on the client(s). you can also notice some weirdness if you're trying to connect from PuTTY and it hangs as opposed to giving the "____ is unavailable: disconnect" error (not sure of the exact wording) that you usually get when the connection is killed by the server, either through a disconnect or through the server shutting down, etc. a lot of factors go into this. specifically we want to examine the "ClientAliveInterval" and "TCPKeepAlive" variables of the sshd_config and the "ConnectTimeout", "ExitOnForwardFailure", "ServerAliveCountMax", "ServerAliveInterval", "SetupTimeOut", and "TCPKeepAlive" variables in /etc/ssh/ssh_config (and ~/.ssh/config if it exists).

I suspect the later is due to a 3rd party firewall port-forward (ie: watchguard or firebox), but I'm not totally sure. But I do get this on some boxes with a Linux firewall, so is there a setting I should be looking for?

pretty sure it's a keepalive thing on the client end, at this point. i've also had cases where it was line noise- the second i moved the server to a different cat5e line in the network, the connection was crystal clear and i wouldn't get dropped for days (when i was on the network, that is).

--
W. Chris Shank
ACE Technology Group, LLC
www.myremoteITdept.com
(610) 640-4223

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