Hello! Today I will be teaching you how to install and configure UFW on Debian or Ubuntu based machines. I hope that some of you find this helpful!
Prerequisites: You will need a root account and/or an account with sudo access. You also will need a machine using the apt package manager (Ubuntu, Debian.)
Installing UFW
For most machines UFW is insalled by default, however if this is not the case. You can install with
sudo apt install ufw
Allowing IPV6 Configuration
In most versions, IPV6 is enabled by default. If it is not however, you can edit the UFW config file to enable it.
sudo nano /etc/default/ufw
And change the value
ipv6=yes
Setting Default Policies
By default UFW blocks all incoming traffic and allows all outgoing. To set custom policies for applications. For this tutorial we will mostly just deny all traffic to begin with.
sudo ufw deny incoming
sudo ufw deny outgoing
Allowing SSH Connections *Optional
If you want some applications to network, or you use SSH you can enable the OpenSSH profile through UFW by typing
sudo ufw allow openssh
or
sudo ufw allow ssh
Turning on UFW
You can now start the UFW service by typing the following command
sudo ufw enable
The firewall is now enabled and following our instructions.
Opening/Allowing Applications and Ports Through Firewall
If you want to use a browser like firefox or need to use a certain port you can use this syntax
sudo ufw allow http
sudo ufw allow https
sudo ufw allow [port number]
Allowing Specific IP Addresses
If you have a specific computer that you want to connect to, you can let it through the firewall through
sudo ufw allow from [IP address]
or for a certain port
sudo ufw allow from [IP address]/[port]
Denying connections
You can deny certain services or users with
sudo ufw deny [service]
Deleting Rules
If you want to remove one of your previous rules you can do that with
sudo ufw status numbered
to display all rules
sudo ufw delete [rule number]
Conclusion
I hope that you enjoyed this short guide of UFW. If you want me to add anything, please comment down below! 
-CKjones