How to Keep Your SSH Terminal Connected and from Being Automatically Disconnected by the Remote Computer  
by Anne P. Mitchell, Esq. - Last updated 07/04/2007

Don’t you just hate it when you are connected to a remote computer system via ssh, and you do something in another window, only to find when you return to your ssh session that you’ve been automatically disconnected by the remote system, and you have to log in all over again? Here’s how make it so that you can stay connected to the remote computer with ssh no matter how long you are idle.

First, you will need to find your ssh configuration file; if you don’t have one, you will need to create it.

On a Mac, for example, your personal ssh configuration file is at:

~/.ssh/config

If you want to create this change for the entire computer (including other users), you will instead want to use the file found at /etc/ssh/ssh_config

On other types of computers, you can find the ssh configuration file in similar locations (and the individual user file is almost always going to be at ~/.ssh/config).

Now, make a backup copy of the file, just to be safe.

Then edit the actual file to include this simple line:

ServerAliveInterval 300

That’s it!

Now your computer will let the remote server know, every X seconds, that your computer is still there and should not be connected. The number in that line is the number of seconds - in the example above it’s 300 seconds, or five minutes. You may need to adjust the number to suit your own needs, but 300 is usually sufficient.

That’s all there is to it!