8.6 Configure and Verify the Advertising of a Default Route

Step 1: Configure default route advertisement on R2.

Configure R2 to advertise a default router to R1. R2 does not necessarily have to have a default route of its own. Core internet routers that have full internet routing tables and do not require a default route are referred to as being in a default-free zone (DFZ).

R2(config)# router bgp 500

R2(config-router)# neighbor 10.1.2.1 default-originate

Step 2: Verify default route advertisement on R1.

a. Examine R1’s routing table to verify that it has received a default route.

R1# show ip route bgp | begin Gateway

Gateway of last resort is 10.1.2.2 to network 0.0.0.0

B* 0.0.0.0/0 [20/0] via 10.1.2.2, 00:00:37

192.168.2.0/24 is variably subnetted, 2 subnets, 2 masks

B 192.168.2.0/27 [20/0] via 10.1.2.2, 21:24:43

B 192.168.2.64/26 [20/0] via 10.1.2.2, 21:24:43

B 192.168.3.0/24 [20/0] via 10.1.2.2, 12:41:58

b.Examine R1’s BGP table to verify that it has received a default route.

R1# show ip bgp

Network Next Hop Metric LocPrf Weight Path

*> 0.0.0.0 10.1.2.2 0 500 i

*> 192.168.1.0/27 0.0.0.0 0 32768 i

*> 192.168.1.64/26 0.0.0.0 0 32768 i

*> 192.168.2.0/27 10.1.2.2 0 0 500 i

*> 192.168.2.64/26 10.1.2.2 0 0 500 i

*> 192.168.3.0 10.1.2.2 0 500 300 i