Three Excellent Linux Router Distros + 1 BSD
Special purpose appliance distributions are one of the things that Linux does extremely well. You can find any number of task-specific appliances from either Turnkey Linux or on the VMware Virtual Appliance marketplace. In this article we'll take a look at four different specialized distributions targeted at the job of an Internet firewall or traffic router. Each one has its own set of features and distinctive, and we'll try to highlight those for you.
The first thing we need to do before we get started is to define what a router is or does. In the most basic sense of the term, a router forwards packets from one network to another. To really understand what's going on you need to picture how Internet traffic moves from one computer to another. If you do a Google search for OSI 7-layer model, you'll find any number of pictures and references describing network traffic as it happens from the lowest layer (physical) up to the highest layer (application). Most routers typically sit at layer 3 since they use an IP address to make decisions on what to do with the data. Most firewalls typically involve the basic functions of a router along with filtering and physical separation, meaning two separate network connections, to do their job.