FreeBSD6 Unleashed

Routing

You’ve already learned a little bit about how IP routing works, but we’ll now cover it in a little bit more detail. Configuring routes properly is one of the great skills one can develop in networking, and it pays to be able to do it correctly—or at least to have a working understanding of it so that you can perform administrative tasks that require interfacing with the routing table, such as portsentry (which we will discuss in Chapter 30, “Network Security”).

A router is any device configured to act as a router, which includes actual dedicated devices sold by Cisco or its competitors, or regular computers that can do the job in a pinch. Routers work by maintaining a routing table—a set of rules that says where packets that match certain ...