How to use
$ sudo ufw allow ssh/tcp
$ sudo ufw enable
$ sudo ufw status numbered
$ sudo ufw delete 2
$ sudo ufw allow from 10.0.0.0/8 to any port 8080/tcp
sudo ufw allow proto tcp from 192.168.0.0/16 to any port 8080
sudo ufw allow in on eth0 from 10.8.0.0/24 to any port 22 proto tcp