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Webcast-Catalyst9k
New Member

PPP authentication

Hi Experts,

If i have two routers (point-to-point), one of them configured with ppp authentication CHAP and the other configured with ppp authentication PAP , the line protocol will be down or up ?

Regards,

Ibrahim Alwahidi

7 REPLIES

Re: PPP authentication

Hi Ibrahim,

The PPP link won't come up unless the authentication succeeds (both sides must support either PAP or CHAP simultaneously):

Troubleshooting PPP (CHAP or PAP) Authentication

http://www.cisco.com/en/US/tech/tk713/tk507/technologies_tech_note09186a00800b4130.shtml

HTH, please do rate all helpful replies,

Mohammed Mahmoud,

Hall of Fame Super Bronze

Re: PPP authentication

It will be up.

Router 1

username R2 password CISCO

int s0/0

en ppp

ppp authentication chap

ppp pap sent-username R1 password CISCO

Router 2

username R1 password CISCO

int s0/0

en ppp

ppp authentication pap

ppp chap hostname R2

ppp chap password CISCO

Re: PPP authentication

Hi Edison,

You are absolutely correct, the case you are suggesting shall work, as R2 requires any PPP initiated to it to be PAP (ppp authentication pap) authenticated and since R1 can authenticate itself using PAP it will succeed and vice versa for R1 with CHAP (ppp authentication chap), i guessed that the original poster's question involved that each side is only configured with one different method as in and out.

HTH,

Mohammed Mahmoud.

New Member

Re: PPP authentication

Thanx Edison,

But i want to ask u another question about that can i put any username that i want for example

instead of using username R1 , i want to use username Linux...

Regards,

Ibrahim Alwahidi

Hall of Fame Super Bronze

Re: PPP authentication

Then you need to create an username Linux on R2.

Re: PPP authentication

Hi Ibrahim,

Like Edison has said, you can change the username like you can on the calling router (the router initiating the session), but always keep in mind the router authenticating the other router (we'll call it the server) must have a local entry of this username in order to be able to authenticate the calling router with, as i've told you before on the other thread think of it as a client server issue.

HTH,

Mohammed Mahmoud.

Hall of Fame Super Bronze

Re: PPP authentication

Router 1

username R2 password CISCO

int s0/0

en ppp

ppp authentication chap

ppp pap sent-username Linux password CISCO

Router 2

username Linux password CISCO

int s0/0

en ppp

ppp authentication pap

ppp chap hostname R2

ppp chap password CISCO

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