ssh tip of the day

If you ssh to hosts beyond a firewall or from within a NATted network then you’ll have noticed that SSH sessions timeout and get disconnected. I found that setting the TMOUT variable to 0 helped when not going through a firewall, and it must have been the firewall disconnecting an idle session otherwise.
Add this line to the sshd_config of the server and restart sshd. This will send a keep alive signal to the client every 360 seconds.

ClientAliveInterval 360

man 5 sshd_config will give you more information about that. This works in OpenSSH. I’m not sure if it’ll work elsewhere.

Author: Donncha

Donncha Ó Caoimh is a software developer at Automattic and WordPress plugin developer. He posts photos at In Photos and can also be found on Google+ and Twitter.

4 thoughts on “ssh tip of the day”

  1. This is a good tip. My users have been having this issue as well at a remote office, but in my case, it was my Juniper Netscreen causing the problems. I increased the timeout for that service and the issue went away

  2. Awesome! Keep the great posts coming. This blog is a great reference for people who want to get stuff done and need a plain-English explanation.

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