Refer to the exhibit.
Assume that all of the router interfaces are operational and configured correctly. How will router
R2 be affected by the configuration of R1 that is shown in the exhibit?
A.
Router R2 will not form a neighbor relationship with R1.
B.
Router R2 will obtain a full routing table, including a default route, from R1.
C.
R2 will obtain OSPF updates from R1, but will not obtain a default route from R1.
D.
R2 will not have a route for the directly connected serial network, but all other directly
connected networks will be present, as well as the two Ethernet networks connected to R1.
Explanation:
“ip route 0.0.0.0 0.0.0.0 serial0/0” is causing a loop. configuration is going to cause
a loop and the link between R1 and R2 will be congested, OSPF will not perform relationship
between them. From its name, OSPF is a Link-State routing protocol, and the link state between
R1 and R2 is simply down or something like that.
can someone explain this in a simpler way?
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The answer given is wrong. The correct answer is B. I have seen conflicting information on this question so I built this exact scenario in a lab. R2 will get a full routing table, including a default route – even though, yes, it does introduce a routing loop. However, the default route does NOT get used in forming an adjacency since the two routers are directly connected.
R2s routing table will appear as follows:
Gateway of last resort is 172.16.100.1 to network 0.0.0.0
172.16.0.0/16 is variably subnetted, 8 subnets, 4 masks
C 172.16.16.0/20 is directly connected, Loopback0
L 172.16.16.1/32 is directly connected, Loopback0
C 172.16.32.0/22 is directly connected, Loopback1
L 172.16.32.1/32 is directly connected, Loopback1
C 172.16.100.0/30 is directly connected, Serial0/0/0
L 172.16.100.2/32 is directly connected, Serial0/0/0
O 172.16.100.65/32 [110/65] via 172.16.100.1, 00:00:23, Serial0/0/0
O 172.16.100.129/32 [110/65] via 172.16.100.1, 00:00:23, Serial0/0/0
O*E2 0.0.0.0/0 [110/1] via 172.16.100.1, 00:00:23, Serial0/0/0
and, ospf neigh….
R2#sh ip ospf neigh
Neighbor ID Pri State Dead Time Address Interface
172.16.100.129 0 FULL/ – 00:00:31 172.16.100.1 Serial0/0/0
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Answer B is correct. I configured the scenario in GNS3 and got the same result as rob.
Hope it helps someone.
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ip route 0.0.0.0 0.0.0.0 serial0/0 is causing loop. configuration is going to cause a loop and the link between R1 and R2 will be congested. OSPF will not perform relationship between them. From its name OSPF is a link state routing protocol and the link state between R1 and R2 is simply down or something like that.
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B is correct as argumented above.
Created the topology in Packet Tracer and GNS3 with version 12.x IOS routers, both result in OSPF neighbor relationship between R1 and R2 with the OSPF routes and static route exchanged.
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Solid troubleshooting work there
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