13.1. Packet forwarding: a closer look
Before we jump into the management of routing tables, let’s take a more detailed look at how the tables are used. Consider the network shown in Exhibit A.
Figure A. Example network
Router R1 connects the two networks, and router R2 connects one of the nets to the outside world. (For now, we assume that R1 and R2 are Linux computers rather than dedicated routers.) Let’s look at some routing tables and some specific packet forwarding scenarios. First, host A’s routing table:
A$ netstat -rnKernel IP routing tableDestination Gateway Genmask Flags MSS Window irtt Iface199.165.145.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 ...
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