Learning by Doing: CISCO Certified Network ... - SCN Research

“real-world” scenario. Undo all of the last steps. This time use similar
commands except the username and passwords are set a bit differently. The
username must match the hostname of the destination router. Use the line
between leftist and urvile to set up chap.
leftist(config)#int s0/0
leftist(config-if)#enc ppp
leftist(config-if)#ppp authentication chap
leftist(config-if)#exit
leftist(config)#username prophet password cisco
This will set up a username to “dial-in” and be “authenticated” to the urvile
router. We chose to use the username prophet and are obligated to use the
password cisco since we already set it up in our router basics. Next, on urvile, we
use similar commands except that we set the username to the router which will be
calling in. We must also include the hostname that will be calling in to urvile.
urvile(config)#int s0/0
urvile(config-if)#enc ppp
urvile(config-if)#ppp authentication chap
urvile(config-if)#ppp authentication chap callin
urvile(config)#ppp chap hostname prophet
urvile(config-if)#exit
urvile(config)#username leftist password cisco
Don’t forget to change the settings on both sides! (Use S0/1 on urvile.) Notice
how we now have to use the hostname of the other router and the “enable secret”
of “cisco” (the encrypted one). You will know when you have the right
combination of user names and passwords when the line and protocol both come
up.
11. Then view the CHAP with the same debugs…debug tasks, debug negotiation, and
debug authentication. They should be similar to the PAP ones except that there is
a three-way handshake and our passwords are encrypted. Can you see it?
Challenge Lab or Supplemental Activities:
1. Try switching the order of which router will be called into and which one will
do the calling. Why would this be important? Why would you want to do
this?
2. Try configuring PAP and CHAP on the same router. Why would you want to
do this?
3. Can we do any authentication with HDLC? Try it and find out. When would
you want to use PPP with authentication and when would you want to use
HDLC?
4. What are the other debug options available with PPP? What does each of
them do?
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