The goal of this report is to investigate firewalls from both the software and the hardware architecture on their security, functionality, effectives and how the configuration works. The test will consist of scans from Nessus and Nmap which both scans for information and vulnerabilities on the target device. The scans will be performed by first make a basic configuration of the firewall to test its base security. In the second scan will the devices be security configured and rescanned to give an overview on how secure they have become. The target software firewalls used in this test consists of a Debian 4.0, Mikrotik and a Windows 2003 server. The Debian and Windows distributions are both a full OS and have firewall capabilities while Mikrotik is a Linux distribution optimized to work as a firewall. A Cisco 2801 router will also be tested as it is a hardware device optimized for packet handling and have firewall capabilities, and as a router it's likely to already be in a company's network. Finally a Cisco ASA 5510 hardware firewall will be tested to show how a device designed as a firewall will compare to the other devices. The result shows that a Device like the ASA 5510 is clearly superior to any of the other devices in its performance, however the cost efficiency might be in question. The use of a software firewall might be more cost efficient, but might also be more vulnerable as other applications can be run at the OS.