You want to make your system more secure.
You want to use a firewall in your Ubuntu
Ubuntu has a firewall that normally is disabled. It's called "Firestarter". To install and activate "Firestarter" you have to do the following steps:
First you have to install "Firestarter". It's easily done with this command: sudo apt-get install firestarter
After the packet is installed you have to start and configure "Firestarter". Click on System—>Administration—>Firestarter
On the Welcome screen click forward
Select Network Device setup and click forward
Select if you have any internet connection sharing and click forward
On the next screen you need to click on the check box next to "start firewall now" and click on save
Now you should see the firestarter GUI
About the Author
Wim Peeters is electronics engineer with an additional master in IT and over 30 years of experience including time spent in support, development, consulting, training and database administration. Wim has worked with SQL Server since version 6.5. He has developed in C/C++, Java and C# on Windows and Linux in different European countries and different European languages. He writes knowledge base articles to solve IT problems and publishes them on the Lubby Knowledge Platform where he is one of the most important contributors and the main developer.