zdnet[.]com/article/an-uncomplicated-introduction-to-uncomplicated-firewall/
Thought this might be useful for folks like gergn who are starting to use Linux more often.
... Starting around 1998, if you want to manage the security of a system, you had to learn iptables (which is a suite of commands for manipulating the Netfilter packet filtering system).For example, if you want to allow all incoming secure shell (SSH) traffic, you might have to issue commands like this:
sudo iptables -A INPUT -p tcp --dport 22 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT sudo iptables -A OUTPUT -p tcp --sport 22 -m conntrack --ctstate ESTABLISHED -j ACCEPTThat's all fine and good if you have time to not only master the Linux operating system, but also know the finer points of managing a complicated security system...
Uncomplicated Firewall (UFW) is a frontend for iptables, which focuses on simplicity. Compared to iptables, UFW is a leisurely stroll through the park that anyone can handle.
If the command line isn't your jam, there's always a handy GUI tool to make it even easier. One such tool is GUFW, which allows you to point and click your way to UFW firewall rules.
