What are three reasons an OSPF neighbor ship would be stuck in ExStart? (Choose three.)
A.
The LSA database exchange is not yet completed.
B.
There is an MTU mismatch between the OSPF routers.
C.
There is an interface-type mismatch between the OSPF routers.
D.
There is a unicast communication problem between the OSPF routers.
E.
Both OSPF routers are using the same router ID.
Explanation:
Should be B,C and E
B,D and E seems to be correct
https://prasadkeni.wordpress.com/2012/02/14/ospf-neighbor-stuck-in-exstartexchange/
A C E are incorrect
B. There is an MTU mismatch between the OSPF routers. …gets to EXCHANGE.
E. Both OSPF routers are using the same router ID. …doesn’t even gets to EXCHANGE.
C. There is an interface-type mismatch between the OSPF routers. …OSPF works fine.
Options A & D are totally irrelevant.
So only valid answer is just B but keeping keyword “EXCHANGE” in mind.
At the max we have only 2 valid options B & E. No valid 3rd option i can see here.
Question says ExStart..Not EXCHANGE
https://forum.ivorde.com/ospf-neighbors-stuck-in-exstart-case-1-interface-type-mismatch-t19291.html