How To Set Up/Enable a Firewall with UFW on Ubuntu

UFW, or Uncomplicated Firewall, is an interface to iptables

Prerequisites

To follow this tutorial, you will need:

UFW is installed by default on Ubuntu. If it has been uninstalled for some reason, you can install it with sudo apt install ufw.

$ sudo nano /etc/default/ufw

Then make sure the value of IPV6 is yes.

$ sudo ufw default deny incoming
$ sudo ufw default allow outgoing

$ sudo ufw allow ssh

$ sudo ufw allow 22

$ sudo ufw enable

$ sudo ufw allow 80

$ sudo ufw allow 443

$ sudo ufw allow 6000:6007/tcp
$ sudo ufw allow 6000:6007/udp

$ sudo ufw allow from 203.0.113.4

$ sudo ufw allow from 203.0.113.4 to any port 22

$ sudo ufw allow from 203.0.113.0/24

$ sudo ufw allow from 203.0.113.0/24 to any port 22

$ sudo ufw deny http

$ sudo ufw deny from 203.0.113.4

$ sudo ufw status numbered

$ sudo ufw delete 2

$ sudo ufw delete allow http

$ sudo ufw delete allow 80

$ sudo ufw status verbose

$ sudo ufw disable

$ sudo ufw reset