Use
the neighbor next-hop-self command to prevent routing failure
between 2 routers that do not have a direct connection.
Scenario:
Router C learns about network
192.68.11.0/24 via EBGP from Router B with a next hop of 10.1.1.1,
which is the IP address of the external neighbor to router B. However,
Router C does not have a direct connection to Router A and therefore
cannot reach the next hop. This will cause routing to fail. You will
need to use the neighbor next-hop-self command to remedy this
situation.
Tasks:
Cable the lab and all interfaces as
shown in the diagram. Don't forget the no shutdown command!
Configure OSPF routing between
routers B and C. Put both routers in area 0.
Router B(config)#router ospf 1
Router B(config-router)#network 10.2.2.0 0.0.0.255 area 0
Router B(config-router)#network 10.3.3.0 0.0.0.255 area 0
Router B(config-router)#passive-interface serial 0
Router C(config)#router ospf 1
Router C(config-router)#network 10.2.2.0 0.0.0.255 area 0
Router C(config-router)#network 10.4.4.0 0.0.0.255 area 0
Verify that Router B can
successfully ping 10.1.1.1 and all interfaces on Router C.