UFW, or the “Uncomplicated FireWall”, UFW use iptables to manage it’s firewall rules, you may need this while your are using ubuntu or Debian server.

it’s very simple to use

Firstly instal UFW using following command

apt-get install ufw

You can then set it to allow outgoing traffic and reject incoming traffic by default with the following commands:

ufw default allow outgoing
ufw default allow outgoing

You will need to then enable the firewall:

ufw enable

You can then open specific ports using the following command (remember to replace $PORT with the port number you wish to open, and $PROTOCOL with either tcp or udp:

ufw allow $PORT/$PROTOCOL

If you are looking to open the same port for TCP and UDP, you can just leave out the /$PROTOCOL part:

ufw allow $PORT