I wanted to test removing all default iptable rules and replacing them with my own, using ufw. I have a very simple LAN that just needs 1/2 dozen ports, and iptable defaults are causing major conflicts when I try blocking IP's.
So I created the ufw rule: ufw allow 22/tcp then I issued: echo "ufw reload" | at now + 1 min and iptables --flush with the expectation that my ssh session would be restored after a minute. But that didn't happen - I had to reboot the server running ufw. Is there anything else in the default iptables that is mandatory to restore a ssh session?