I'm running EIGRP key-chains and authentication from one router to another and after configuring one side i get the expected routes start to flap. But also i can still ping from one end of the link to the other. Why is that if the authentication on both sides are different? If i can still ping what's the purpose of the authentication in the first place?
I'm basically trying to ask "what's the purpose of authentication?"
The key-chains and key-strings are the same across all routers, but i didn't authenticate (that word becomes a pain to keep typing out) across all the interfaces - just on router 1.