An SSH/Firewall tip for you sysadmins.

When SSHing, don’t make any changes to the current firewall script. Make a copy of it. Make your changes to the copy, and don’t rename the copy to whatever the current script is called. When you are ready for a test of the altered script:

1. Atart a second SSH session and issue a shutdown -r 5
2. Run the new script

This should give you enough time to see if the new script works. If your new script is messed up and locks you out, the timed shutdown command will call the original script upon reboot.

If the new script works as designed simply make a back up of the original and rename the new script to the original name.

Thanks SocketCreep!

p.s. ‘shutdown -c’ cancels the shutdown.