SSH connections started dropping left and right a few days ago. I thought at first it was a problem with my connection, our DSL connection in Beirut, Lebanon is getting a lot better this last year. But it still had its quirks now and then and I blamed the wires and bad weather.
But it happened again the second day and the third, and it was becoming really annoying with jobs killed in the middle of execution when I forget to start a screen.
Long story short, it seems that some settings were removed or reset after an upgrade in Ubuntu on my home machine. This is what I added in /etc/ssh/ssh_config (not sshd_config!)
Host * ServerAliveInterval 30 ServerAliveCountMax 5
And that’s it!
If you don’t want to edit the system-wide configuration, you can always edit ~/.ssh/config with the same for similar effect.