The configuration of R1 to R6 are posted below for your reference, useless lines are omitted: Which key chain is being used for authentication of EIGRP adjacency between R4 and R2?
正解:A
Explanation/Reference: Explanation: Check on both R2 and R4: To successfully authenticate between two EIGRP neighbors, the key number and key-string must match. The key chain name is only for local use. In this case we have key number "1" and key-string "CISCO" and they match so EIGRP neighbor relationship is formed.