Uncomplicated Firewall. Frontend for iptables aiming to make configuration of a firewall easier.
# To enable ufw:
ufw enable
# To disable ufw:
ufw disable
# To show ufw rules, along with their numbers:
ufw status numbered
# To allow incoming traffic on port 5432 on this host with a comment identifying the service:
ufw allow 5432 comment "Service"
# To allow only TCP traffic from 192.168.0.4 to any address on this host, on port 22:
ufw allow proto tcp from 192.168.0.4 to any port 22
# To deny traffic on port 80 on this host:
ufw deny 80
# To deny all UDP traffic to port 22:
ufw deny proto udp from any to any port 22
# To delete a particular rule. The rule number can be retrieved from the ufw status numbered command:
ufw delete rule_number