BSCI - EIGRP - Adjacency Requirements

The following criteria need to be meet before an EIGRP adjacency will form:
i) Authentication (if in place)
ii) AS Number
iii) Source IP MUST be the primary address for the interface - secondary IP's will not result in the adjacency forming
iv) K values must match

N.B. - Timers do not have to match but they must be equal.
- Adjacency will flap if timers are mismatched.
- Therefore ensure you have a reliable time source.