Never thought to look for an HN discussion on it, but it turns out that there is one.
IIRC, one thing the series doesn't mention is that a particular option needs to be explicitly specified in order to maintain port tunnels. By default, as long as the SSH connection succeeds during an AutoSSH reconnect, it will chug along happily without the port-forward if it's still blocked from the previous connection before the drop.
Every time I need to set it up, I go through this series of very short and digestible articles.
https://news.ycombinator.com/item?id=10937277 (discussion for the third in a 4-part series).
Never thought to look for an HN discussion on it, but it turns out that there is one.
IIRC, one thing the series doesn't mention is that a particular option needs to be explicitly specified in order to maintain port tunnels. By default, as long as the SSH connection succeeds during an AutoSSH reconnect, it will chug along happily without the port-forward if it's still blocked from the previous connection before the drop.