Verifying OSPF Configuration
There are several ways to verify proper OSPF configuration and operation, and in the following
sections I’ll show you the OSPF show commands you need to know in order to do this. I’ll
start by showing the routing table of the Corp router. Here in Table 4.10 are the commands
we’ll use to verify OSPF:
Verifying OSPF
Command Meaning
show ip route Displays the router’s routing table
show ip ospf Displays OSPF information for one or all OSPF processes
running on the router
show ip ospf database Shows the topological database used in OSPF
show ip ospf interface Displays all interface-related OSPF information
show ip ospf neighbor Summarizes the pertinent OSPF information regarding
neighbors and the adjacency state
show ip ospf protocols Shows routing protocol information
So, let’s issue a show ip route command on the Corp router:
10.0.0.0/24 is subnetted, 12 subnets
O 10.1.11.0 [110/65] via 10.1.5.2, 00:01:31, Serial0/2/0
O 10.1.10.0 [110/65] via 10.1.5.2, 00:01:31, Serial0/2/0
O 10.1.9.0 [110/74] via 10.1.4.2, 00:01:31, Serial0/1/0
O 10.1.8.0 [110/65] via 10.1.4.2, 00:01:31, Serial0/1/0
O 10.1.12.0 [110/66] via 10.1.5.2, 00:01:31, Serial0/2/0
C 10.1.3.0 is directly connected, Serial0/0/1
C 10.1.2.0 is directly connected, Serial0/0/0
C 10.1.1.0 is directly connected, FastEthernet0/1
O 10.1.7.0 [110/74] via 10.1.3.2, 00:01:32, Serial0/0/1
[110/74] via 10.1.2.2, 00:01:32, Serial0/0/0
O 10.1.6.0 [110/74] via 10.1.3.2, 00:01:32, Serial0/0/1
[110/74] via 10.1.2.2, 00:01:32, Serial0/0/0
C 10.1.5.0 is directly connected, Serial0/2/0
C 10.1.4.0 is directly connected, Serial0/1/0
The Corp router shows the found routes for all 12 networks, with the O representing OSPF
internal routes (the Cs are obviously the directly connected networks). It also found the dual
routes to networks 10.1.6.0 and 10.1.7.0. OSPF uses bandwidth only to determine the best
path to a network.