> It's something that can probably be fixed with the right ssh_config/sshd_config, but I can't for the life of me figure out the right incantations.
Have you tried something like this? It does a common TCP/IP socket for each remote host and does application-level pings every 4 minutes to keep the socket active. Solved most of my "stay connected" issues.
Host *
ControlPath ~/.ssh/cm-%r@%h:%p
ControlMaster auto
ControlPersist 10s
ServerAliveInterval 240
Have you tried something like this? It does a common TCP/IP socket for each remote host and does application-level pings every 4 minutes to keep the socket active. Solved most of my "stay connected" issues.