O'Reilly logo

UNIX System Administration Handbook, Third Edition by Trent R. Hein, Evi Nemeth, Garth Snyder, Scott Seebass

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

14.1 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.

Exhibit A Example network

image

Router R1 connects the two Ethernets, and router R2 connects one of the nets to the outside world. (For now, we’ll assume that R1 and R2 are UNIX 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 -rnRouting tablesDestination           Gateway              Flags    Refs    Use            If127.0.0.1            127.0.0.1             UH       6         563131      lo0 ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required