Which two statements are true when configuring OSPF authentication? (Choose two.)
A.
An OSPF link can support both simple password and MD5 authentication at the same time.
B.
An MD5 password requires a key ID.
C.
You can configure multiple MD5 passwords simultaneously on the same link.
D.
If the MD5 password negotiation fails, you can configure OSPF to automatically use a simple
password as a backup.
Explanation:
You can configure IPsec authentication together with either MD5 or simple authentication
Because OSPF performs authentication at the area level, all routing devices within the area must have the same authentication and corresponding password (key) configured. For MD5 authentication to work, both the receiving and transmitting routing devices must have the same MD5 key. In addition, a simple password and MD5 key are mutually exclusive. You can configure only one simple password, but multiple MD5 keys.