ufw

Uncomplicated Firewall. Frontend for iptables aiming to make configuration of a firewall easier. More information: https://wiki.ubuntu.com/UncomplicatedFirewall.

• Enable ufw:

ufw enable

• Disable ufw:

ufw disable

• Show ufw rules, along with their numbers:

ufw status numbered

• Allow incoming traffic on port 5432 on this host with a comment identifying the service:

ufw allow 5432 comment "Service"

• 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

• Deny traffic on port 80 on this host:

ufw deny 80

• Deny all UDP traffic to ports in range 8412:8500:

ufw deny proto udp from any to any port 8412:8500

• Delete a particular rule. The rule number can be retrieved from the ufw status numbered command:

ufw delete rule_number