Which command shows only OSPF routes installed into the routing table?
A. show ip route
B. show ip ospf route
C. show ip route ospf
D. show ip ospf
E. show ip ospf database
Explanation:
The correct answer is show ip route ospf.
The show ip route ospf command shows you all the OSPF learned routes in the routing table. An example of the command and its output are below with an explanation of some of the terminology.
Router5# show ip route ospf
O IA 10.0.0.0/8 [110/65] via 5.0.0.2, 00:00:20, Serial1/1/0
S 0.0.0.0/0 [110/1] via 5.0.0.2, 00:00:20, Serial1/1/0
O E2 172.16.0.0 [110/25] via 5.0.0.2, 00:00:30, Serial1/1/0
• – indicates that the route was learned from OSPF.
• IA – indicates that the route is an inter area route, meaning it was learned via summary type 3 link state advertisements (LSAs).
• S – indicates that a static default route has been configured.
• E2 – indicates that the route is an external router redistributed from another protocol.
• Via – indicates the next hop address to use and the local interface from which to send
• [110/65]- indicates the administrative distance with the first value and the cost in the second (AD/cost).
The full legend of the possible route codes is below:
Codes: C – connected, S – static, R – RIP, M – mobile, B – BGP
D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF external type 1, E2 – OSPF external type 2
i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area
* – candidate default, U – per-user static route, o – ODR
P – periodic downloaded static route
The commands below can be used to monitor and verify OSPF operation:
show ip route – displays known routes and from which protocol the routes were discovered, but for all routing protocols, not just OSPF.
show ip ospf – displays the number of times the SPF algorithm has run and the default Link State Update (LSU) interval, but not the OSPF routes.
show ip ospf database – displays the router ID, the OSPF process ID, and the contents of the topological database but not the routing table.
There is no show ip ospf route command.
Objective:
Layer 3 Technologies
Sub-Objective:
Configure and verify OSPF operations
References:
Cisco > Cisco IOS IP Routing: Protocol-Independent Command Reference > show ip route