The Linux operating system is gaining more and more popularity day by day. The popularity of its stability and security. Linux systems are considered more secure and actually they are. Security is provided at each and every level. The security level but still can be breached. To make it more secure a firewall is required.
A firewall can help you to stop incoming attacks, allow only certain type of traffic to pass through or even block some websites.
Firestarter is nice firewall. It is available for almost all Linux distributions. The main features firestarter firewall security are:-
1.) Internet Sharing.
3.)Can act as DHCP server.
4.)Blacklist or whitelist traffic
5.)Real time traffic monitoring.
Now How to Setup Firestarter firewall on your ubuntu linix to make it more secure
Step1.) Type the following command in the terminal.
sudo apt-get install firestarter
Step3.) A wizard like this appears.
Step4.) Select the interface on which you want to enable the firewall
Step5.)Now you can enable the internet sharing if you have two network cards. One is for receiving internet connection and other for sharing the internet connection.
Note:- You can also use this as a DHCP server for your system but you need to install DHCP server first.
sudo apt-get install dhcpd
Step6.) Now click on the events tab and you see all the events or established session. There is a session that is displayed in red. The sessions displayed in red means a critical event. In my case it was a ssh connection
Step7.) Now you can make your linux more secure using the firestarter traffic control policy.
The traffic control policy can be defined as permissive or restrictive. Permissive means allowing all connections except the connections which are blacklister. Restrictive policy means blocking all connections except the ones mentioned.
These policies can be applied on all outbound and inbound traffic
In this i am blocking connections to helium host.
we can also define so that only few services are blocked eg Our host cannot make a connection to helium for http traffic.
Hope you have understood the basics of firewall and how to use the firestarter firewall. This is just an intro there are lot more things that can be done to make your linux more secure.