I have previously added some netfilter rules via iptables. I'd now like to manage these rules through ufw and to simplify things I wanted to get rid of the current rules and start afresh as if I was using ufw from the start.
sudo iptables --flush to remove all the current rules, then
sudo ufw allow 22 to allow ssh and
sudo ufw enable. I was then booted out of my ssh session so the rule clearly hadn't worked.
I connected back with a console session and compared
sudo iptables -L -v to a different server that was working with ufw and I noticed that the top INPUT chain on this server was empty, whereas the working server had:
Chain INPUT (policy DROP 77 packets, 3613 bytes) pkts bytes target prot opt in out source destination 3842 682K ufw-before-logging-input all -- any any anywhere anywhere 3842 682K ufw-before-input all -- any any anywhere anywhere 422 32270 ufw-after-input all -- any any anywhere anywhere 422 32270 ufw-after-logging-input all -- any any anywhere anywhere 422 32270 ufw-reject-input all -- any any anywhere anywhere 422 32270 ufw-track-input all -- any any anywhere anywhere
It looks as though the flush had cleared out some default rules that ufw had applied to the INPUT chain, is this a correct assumption? If so, a) how do I repair the situation and b) how do I do this process correctly?