Linux – Autostart SSH after reboot

Please don't delete the entire known_hosts file as recommended by some people, this totally voids the point of the warning. It's a security feature to warn you that a man in the middle attack may have happened.

I suggest you identify why it thinks something has changed, most likely an SSH upgrade altered the encryption keys due to a possible security hole. You can then purge that specific line from your known_hosts file:

sed -i 377d ~/.ssh/known_hosts

This deletes line 377 as shown after the colon in the warning:

/home/emerson/.ssh/known_hosts:377

Alternatively you can remove the relevant key by doing the following

ssh-keygen -R 127.0.0.1 (obviously replace with the server's IP)

Please DO NOT purge the entire file and ensure this is actually the machine you want to be connecting to prior to purging the specific key.

UPDATE: For an actual answer see zero_r's answer below

This isn't an answer, but a workaround. Use screen.

When you first log in, run screen. You get another shell, run commands in that. If you're disconnected, the screen process keeps the terminal alive so that your shell and the processes it is running don't fall over. When you reconnect, run 'screen -r' to resume.

There's a bunch more to configuring and using screen, but the above should workaround your problem.