Task 1.7 - PPP CHAP authentication

I found this task very confusing…

The task requested – R3 should authenticate R5 with PPP CHAP
authentication; R5 should reply to this request with the username RackXR5 and a
hash of password CISCO.

INE Solution is…



username RackXR5 password 0 CISCO


interface Virtual-Template 1

 ppp authentication
pap chap



username RackXR3 password 0 CISCO


Correct me if I’m wrong, but is R5 sending the username
RackXR3 with a hash of password CISCO? This doesn’t meet the task requirement.
I couldn’t figure this out during the mock. What do you think?


  • JoeMJoeM ✭✭✭

    Hi ciscoguru72,

    That config is correct.  R5 responds with its own hostname (along with the password for the challenging router (R3).


    To make it clearer, I prefer the more explicit way of doing this (if allowed). 

    The debug is exactly the same.  R5 will respond with its real hostname or "alternative" hostname


               inter <x>

                encapsulation ppp

                ppp chap hostname RackXR5
    <-- "alternative CHAP hostname"
    ppp chap password CISCO



         ---Here is an example debug output for the INE solution:---


     %LINK-3-UPDOWN: Interface Serial0/1, changed state to up
     Se0/1 PPP: Using default call direction
     Se0/1 PPP: Treating connection as a dedicated line
     Se0/1 PPP: Session handle[F5000002] Session id[2]
     Se0/1 PPP: Authorization NOT required
     Se0/1 CHAP: O CHALLENGE id 1 len 30 from "RSRack1R4"
     Se0/1 CHAP: I RESPONSE id 1 len 30 from "RSRack1R5"
     Se0/1 PPP: Sent CHAP LOGIN Request
     Se0/1 PPP: Received LOGIN Response PASS
     Se0/1 CHAP: O SUCCESS id 1 len 4



    Se0/1 PPP: Authorization required
    Se0/1 PPP: No authorization without authentication
    Se0/1 CHAP: I CHALLENGE id 1 len 30 from "RSRack1R4"
    Se0/1 CHAP: Using hostname from unknown source
    Se0/1 CHAP: Using password from AAA
    Se0/1 CHAP: O RESPONSE id 1 len 30 from "RSRack1R5"
    Se0/1 CHAP: I SUCCESS id 1 len 4




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