Chapter 9

1:
A:	Either the IP address or the mask is misconfigured on one of the neighboring interfaces.
2:
A:	One router is configured as a stub area router, and the other is not.
3:
A:	The receiving router is configured for MD5 (type 2) authentication, and the neighbor has no authentication configured (type 0).
4:
A:	The passwords configured on the two routers do not match.
5:
A:	The neighboring interfaces are not configured with the same area ID.
6:
A:	RTA's network statements are in the wrong order. The first statement matches IP address 192.168.50.242 and puts it in area 192.168.50.0.
7:
A:	Link ID 10.8.5.1 is the most likely suspect because its sequence number is substantially higher than the sequence numbers of the other links.