Static routes, by hand

The idea

A laptop behind branchRouter, servers behind hqRouter, two links between the two routers. They know only their own networks until you type their routes: there and back, one address, a backup that floats, and a default.

Steps

1. Only its own networks

   Before typing routes, see what a router does without one. No routes are typed in yet; the laptop pings the web server, 10.0.2.10, behind both routers.

   branchRouter:~# vtysh -c 'show ip route'
   laptop:~# ping -c1 -W2 10.0.2.10

2. A route, and the way back

   A route typed by hand is a static route: it never changes unless someone edits it. branchRouter gets one: 10.0.2.0/24 goes to hqRouter, 10.0.12.3, the next hop. hqRouter gets no route back yet.

   branchRouter:~# vtysh -c 'configure terminal' -c 'ip route 10.0.2.0/24 10.0.12.3'
   laptop:~# ping -c1 -W2 10.0.2.10
   hqRouter:~# vtysh -c 'configure terminal' -c 'ip route 10.0.1.0/24 10.0.12.2'
   laptop:~# ping -c1 -W2 10.0.2.10