The show ip route command shows how to verify RIP on the R3 router.

vyatta@R3:~$ show ip route
Codes: K - kernel route, C - connected, S - static, R - RIP, O - OSPF,
       I - ISIS, B - BGP, > - selected route, * - FIB route
R>* 10.0.20.0/24 [120/3] via 10.0.50.2, dp0p1p6, 00:20:16
R>* 10.0.30.0/24 [120/3] via 10.0.50.2, dp0p1p6, 00:34:04
R>* 10.0.40.0/24 [120/2] via 10.0.50.2, dp0p1p6, 02:15:26
C>* 10.0.50.0/24 is directly connected, dp0p1p6
C>* 10.0.60.0/24 is directly connected, dp0p1p7
C>* 127.0.0.0/8 is directly connected, lo
vyatta@R3:~$

The output shows that routes to the 10.0.20.0/24, 10.0.30.0/24, and 10.0.40.0/24 networks have been learned through RIP and that packets to those networks are forwarded out dp0p1p6 to 10.0.50.2. The 10.0.50.0/24 and 10.0.60.0/24 networks are directly connected.