CCNA Routing and Switching (legacy) — Question 183

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

Answer options

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

Correct answer:

Explanation

The correct command is 'Router(config-if)# ppp authentication chap pap' because it specifically sets CHAP as the primary authentication method and PAP as a fallback. The other options either misplace the command syntax or do not correctly specify PAP as the fallback method.