SSH: Undo Your Network Screwups After You've Lost the Connection

Kyriakos Schwarz

Messing with a firewall or a network over a remote connection? Nerve wracking isn't it? Change the wrong setting and you'll be locked out, unable to fix it.

So why not undo your mistake? Schedule a job to run at a later time that undoes what you're about to do.

at now + 5 minutes <<< 'cp /etc/ssh/sshd_config.old /etc/ssh/sshd_config; service sshd restart'

If you screw up, the job will run and restore things to the way they were. If you your change works, then just run

atq

to check the queue of upcoming at jobs, and

atrm jobNumber

to remove it.