Software Firewalls: Security for your network.
Most of the routers that will be sold nowadays have hardware based firewalls. These firewalls offer a basic security for home users, but often they have only a few configuration options, because of usability problems.
That’s why it is sometimes needed to install a software firewall. The software firewalls offer many configuration options, most of them are able to monitor system activities and software components. They can monitor single programs and their components and detect the changes in behaviour and code of them.
The best software firewalls that I know are Zone Alarm Pro and Outpost Firewall Pro.