Exam 200-125 topic 1 question 17 discussion

Actual exam question from Cisco's 200-125

Question #: 17
Topic #: 1

Scenario -
Refer to the topology. Your company has decided to connect the main office with three other remote branch offices using point-to-point serial links.
You are required to troubleshoot and resolve OSPF neighbor adjacency issues between the main office and the routers located in the remote branch offices.
Use appropriate show commands to troubleshoot the issues and answer all four questions.

Instructions -

An OSPF neighbor adjacency is not formed between R3 in the main office and R6 in the Branch3 office. What is causing the problem?

A. There is an area ID mismatch.
B. There is a PPP authentication issue; the username is not configured on R3 and R6.
C. There is an OSPF hello and dead interval mismatch.
D. The R3 router ID is configured on R6. D

Show Suggested Answer

Suggested Answer: Explanation 🗳️
Here are the relevant parts of the router configs:

We are not sure about the configuration of ppp authentication in this case. Some reports said that only one router has the "ppp authentication chap" command but it is just a trick and is not the problem here. The real problem here is R6 uses the same router-id of R3 (192.168.3.3) so OSPF neighborship cannot be established. In real life, such configuration error will be shown in the command line interface (CLI). So please check carefully for this question.

by rtalada at Jan. 9, 2020, 1:45 a.m.