CCNA R&S Exam Prep Question of the Week

Which command is used to enable CHAP authentication, with PAP as the fallback, on a serial interface?

A. Router(config-if)# authentication ppp chap pap
B. Router(config-if)# authentication ppp chap fallback ppp
C. Router(config-if)# ppp authentication chap fallback ppp
D. Router(config-if)# ppp authentication chap pap

The correct answer is D.

The correct syntax is ppp authentication chap pap. The first (CHAP) is the preffered method, but if the other device is configured for PAP, that will still work.

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