// I am currently using Ubuntu Hardy Heron on my machine and by default no firewall is set up by Ubuntu. Luckily, it is really simple to set up and manage a firewall on Ubuntu. I have done some research, I’ve found that technically speaking Ubuntu does include a firewall :- you could configure everything manually using iptables. However this is a tedious and complicated task. I prefer to have a GUI interface to easily configure the firewall.
After going through some discussion forums for about half an hour trying the best and easiest firewall, I’ve got the choice between Firestarter and Lokkit, which are both easy to use, and requires very little understanding of firewalls to set up. The only problem with these two packages is that they provide few options, and it’s not a good choice if you want to set up a complex firewall. Anyway, I will go for Firestarter which has simple a GUI for Ubuntu iptables, not the firewall itself(as I said above) and of course it provides the necessary protection for my machine.
To install Firestarter:
Step 1. Open the terminal Applications > Accessories > Terminal and then type in
sudo apt-get install firestarter
enter your password. This will install Firestarter firewall on your machine, after installation , exit the terminal.
Step 2. Go to System > Administration > Firestarter
Step 3. The first time you open the application, Firestarter will walk you through a basic configuration wizard. Just enter the setting as shown in the pictures shown below:
Step 4. Click Save and you’re done! The installation is over.
The blue icon below will appear in the system tray after installation and when an intrusion is detected, it will turn red.
The menu where you can monitor programs which are currently using your internet connection.
Congratulations, You got a nice firewall GUI. You can now easily configure your firewall settings with Firestarter. Hope this helps. And for those who want to try the firewall Lokkit, you can start from here.
Host Intruder 
If you are a desktop user, I personally feel you dont need a firewall…all u need to do is to install the security updates sent by ubuntu. firewall is very necessay in cases of servers.
Maybe you are right, but with a firewall, you can monitor which program is accessing the internet. You have a better control on your machine.
You can monitor your connections and programs as follows without installing a firewall:
sudo netstat -cpnut
If you close down your uneeded open ports, what benefit does the firewall give you? what does the firewall do to system performance and resources?
Maybe this will used some resources(very little) but as far as I know all Linux distros come with a firewall and have since kernel 2.0. Since Linux 2.4, the firewall built into the kernel is iptables.
Unless you give iptables some rules, it allows everything. Tools like Firestarter are not firewalls themselves(as said it above) but utilities to make it easier to configure iptables. In other words, it’s just as Graphical User Interface.
Another reason to have a firewall is that if later on you decide to install a new service such as SSH or Remote Desktop (VNC), you will probably want to control who can access these services by installing a software firewall.
Since my Ubuntu desktop is my sole machine that connects directly to the Internet, then I think that it’s a good idea to configure one. By the way, thanks for the command
sudo netstat -cpnut, I never heard about it but it’s very useful.Thank you for posting this guide. You did a good job on it and I like your graphics too.
Hi!
Thanks for the article, very interesting. Can you please post more GUI screenshots next time, although the installation process was helpful too.
Good article! For all the h473rZ – 0-day vulnerabilities have, will, and do exist. If a software service has a 0-day vulnerability and a software service is publically accessible on the web because you have not configured iptables, and a bot/worm/scriptkiddie comes a’knocking, your system has no chance of survival…that is, if the intent is destructive or you have something you wanted kept private. Performance is a non-issue unless you want to block entire subnets, and even then unless you are hit really hard by a botnet (DDoS) be thankful the firewall is stopping it instead of complaining about performance. (botnets aren’t typically used to break into home pc’s unless you are in/famous, big business, or a branch of some government.) Configure iptables already!
Firewall isn’t necessary in Linux indeed, but is there more simpler way for ICS?