Policy Routing Using Linux®

IP Routes

The second major building block of Policy Routing is the usage and concept of IP routes. Under traditional routing this is the only element that is considered, and it is relegated to a single use. Traditionally, all routes were destination based. As discussed in Chapter 2 and fit into the Policy Routing hierarchy in Chapter 3, routes may be based on any and all parts of an IP network packet. Additionally, routes no longer just specify where a packet may be forwarded, but specify additional actions as well.

The full coverage of Policy Routing allows actions on the route both at the host and at the router level. The router level is obvious but why would a host have any participation? The host level is often where the initial participation ...