Via Andy Skelton in 2010, proving once again that great advice is timeless.
With these lines in your SSH config file—usually in .ssh directory in your user home directory—you’ll enjoy a more reliable remote shell session.
# Do not kill connection if route is down temporarily.
TCPKeepAlive no
# Allow ten minutes down time before giving up the connection.
ServerAliveCountMax 30
ServerAliveInterval 20
# Conserve bandwith. (Compression is off by default.)
Compression yes