Firewalls protect network traffic and decide witch traffic to send further and witch traffic will be blocked. All this depends on the rules in the firewall. The firewall is installed between the internal network and the Internet. It is difficult to find a firewall that can protect us against different threats. Firewalls have both advantages and disadvantages and all this make them vulnerable. It is important to understand how the firewall protects the network and how to configure it. This paper gives the reader a clear idea how firewalls can protect against different attacks and improve the security.

Computers are not safe when connected to Internet. This paper is about how to use a personal firewall to protect a computer when connected to Internet. One of the firewalls in this examination is Norton Personal Firewall 2005.

Perkins, “Firewalls 24seven, 2nd Edition” and Brian Komar, Ronald Beekelaar and Joern Wettern “Firewalls for Dummies”. Information has also been collected from Apples home page.

It is important to have knowledge about different attacks against network traffic and also about how to protect against them. To know the risks is the first step to be able to evolve an own strategy; too defend network attack.