If you are using Linux and you have been wondering what you can use to make your system secure via a firewall, you could try out tools with graphical user interface and all those other stuff. In any case, there’s also another method: using iptables.

What are iptables?

iptables are used by system administrators in creating rules for packet filtering, as well as NAT modules. It might seem a little too weird for those who have not much experience on the command line but this is essential so that people would be able to make sure that they are secure, especially if they are connected. Sometimes you never know what’s going on in the background, right? But with tools like this, you’d manage.

There are different states of connection and the nice thing about iptables is that it monitors the state of the connection. It could do redirects and modify or stop data packets. Because of its ability to detect the state of the connection, it is considered as better compared to ipchains.

Making rules

The system administrator makes the rules for the iptables. These rules determine how to deal with network packets. They are grouped into chains.

a. filter table – For filtering packets, obviously.
b. nat table – This sets up how rewriting ports and packets.
c. mangle table – Does it sound terrible? Mangle? But as the name implies, there is some mangling involved because it adjusts packet options.

The thing about these chains, these rules is that the packets that go through these chains would be evaluated according to the rules.

As one of the people I know have told me, you must make sure that you check out the settings of your computer first. Before you even think about downloading anything, make sure you are not vulnerable to some attacks that could happen. Make sure that the important ports are closed and that you’re in stealth. Stay tuned for more IT security tips and news to help you in your everyday life.