How to Install and Setup Uncomplicated Firewall (UFW) and its GUI - GUFW in Ubuntu. Using a Firewall in Ubuntu is optional, unlike Windows it doesn't have many ports open and therefore doesn't need to restrict access into the system. If you are using Ubuntu Server or are hosting a website from your home computer, then a Firewall would be a good thing to implement on your system. If you are doing a lot of Torrenting then it might be a good idea to add a Firewall. Install Instructions Install GUFW: sudo apt-get install gufw Setup GUFW Change status to On Create a new rule e.g. Deny TCP/23 Reboot Test if the firewall is working: sudo ufw status If Firewall doesn't work try the following: sudo ufw disable sudo sed -i 's/ENABLED=no/ENABLED=yes/' /etc/ufw/ufw.conf sudo ufw logging off sudo ufw enable sudo ufw status Example rules to create: 23/tcp, Deny In, Anywhere 6881 (or other torrent port), Allow In, Anywhere 22/tcp, Deny In, 192.168.1.1 137:139/udp, Deny In, 192.168.1.1 139/tcp, Deny In, 192.168.1.1 445/tcp, Deny In, 192.168.1.1 4732/tcp, Deny In, 192.168.1.1 Anywhere, Allow In 192.168.1.0/24 22/tcp, Deny In, Anywhere 137:139/udp, Deny In, Anywhere 139/tcp, Deny In, Anywhere 445/tcp, Deny In, Anywhere 4732/tcp, Deny In, Anywhere Some Common Ports on Ubuntu Home Systems: TCP 22 - SSH (Restrict Access) TCP 23 - Telnet (Prevent Access) UDP 68 - DHCP (Don't block) UDP 137:138 - Samba (Restrict Access) TCP 139 - Samba (Restrict Access) TCP 445 - Samba (Restrict Access) TCP 4732 - Remina Remote Desktop (Restrict Access) UDP 5353 - Avahi Service Discovery (Don't block) To see open TCP Ports sudo netstat -napt | grep LISTEN To see open UDP Ports sudo netstat -napu Wallpaper: http://imgur.com/8FrHx