Routers R1 and R2, currently EIGRP neighbors over their Fa0/0 interfaces (respectively),
both use EIGRP authentication. Tuesday at 8 p.m. the neighborship fails.
Which of the following would not be useful when investigating whether authentication
had anything to do with the failure?
A.
debug eigrp packet
B.
show key chain
C.
show ip eigrp neighbor failure
D.
show clock
Explanation:
The show ip eigrp neighbors failure command is not a valid IOS command. The debug
displays messages that state when a neighborship fails due to authentication each time
Hellos are exchangeD. The show key chain command lists the specific keys that are
currently valid, allowing you to determine if both routers use the same key values in currently
valid keys. The show clock command displays the current time-of-day clock setting on a
router, allowing you to check the valid times of the various keys versus the two router’s
clocks.