Enabling ServerAliveInterval by default

Philip philip at yarra.no-ip.org
Mon Dec 17 10:30:23 EST 2007

On Monday 17 December 2007 05:56:25 Nadav Har'El wrote:
> I'm having a very hard time believing that I have been the only person who
> in the course of the last few years found it harder and harder to keep
> non-LAN ssh connections active without being disconnected after a few
> minutes of inactivity. I've seen this problem on several combinations of
> client and server networks.

+1 here - it also took me a long while to figure out what was going on when I 
had this problem. I wish it had been a default years ago.

It's easy enough to change the defaults on machines under your own control, 
but the biggest problem I had was convincing the administrators of remote 
systems I had to use to change their sshd_config. They are far more 
comfortable staying with the bundled defaults. For some systems, we set up a 
shell alias:

alias ka='while [ 1 ]; do echo -n "."; sleep 120; done'

Then of course you have to remember to run that each time you stop actively 
using a session. In short: PITA.

Regarding Bob Proulx's discussion of "make-dead" vs. "keep-alive" - it's a 
point worth considering. I've usually set an interval of a few minutes, and a 
very large ServerAliveCountMax so that it's used only for keeping the 
connection alive, not disconnecting temporarily-missing clients. Is this 
something worth considering as a default? 

Regards, Philip.

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