PPP CHAP Authentication Problem

[Roopak Sethi]

Hi,

I  am trying to implement PPP chap Authentication on two routers connected  via serial interfaces. I just want to know which router will call which  router and which router will challenge which router.

But according to following link of cisco

http://www.cisco.com/en/US/tech/tk713/tk507/technologies_configuration_example09186a0080094333.shtml

It  is wriiten that If Router 1 Initiates a call to Router 2, Router 2  would challenge Router 1, but Router 1 would not challenge Router 2. This occurs because the PPP authentication chap callin command is configured on Router 1.

So, according to cisco document Router 2 should challenge Router 1. But how in my case Router 1 is challenging Router 2 ???

This is confusing me.. Please help

The configurations are as follows:-

r1---serial link... r2

R1:-

username R2 password 0 12345

interface Serial1/0

ip address 10.10.10.1 255.255.255.252

encapsulation ppp

serial restart-delay 0

no dce-terminal-timing-enable

ppp authentication chap callin

R2:-

username R1 password 0 12345

interface Serial1/0

ip address 10.10.10.2 255.255.255.252

encapsulation ppp

serial restart-delay 0

no dce-terminal-timing-enable

[cadet alain]

Hi,

post your debug output.

Regards.

Alain

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[Roopak Sethi]

Hi Sir,

Following is the debug output:-

>>>>>R1<<<<<<

R1(config-if)#

*Oct  5 13:12:30.227: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/0, changed state to up

R1(config-if)#

*Oct  5 13:13:16.387: Se1/0 PPP: Authorization required

*Oct  5 13:13:16.395: Se1/0 CHAP: O CHALLENGE id 2 len 23 from "R1"

*Oct  5 13:13:16.479: Se1/0 CHAP: I RESPONSE id 2 len 23 from "R2"

*Oct  5 13:13:16.483: Se1/0 PPP: Sent CHAP LOGIN Request

*Oct  5 13:13:16.491: Se1/0 PPP: Received LOGIN Response PASS

*Oct  5 13:13:16.495: Se1/0 PPP: Sent LCP AUTHOR Request

*Oct  5 13:13:16.495: Se1/0 PPP: Sent IPCP AUTHOR Request

*Oct  5 13:13:16.503: Se1/0 LCP: Received AAA AUTHOR Response PASS

*Oct  5 13:13:16.503: Se1/0 IPCP: Received AAA AUTHOR Response PASS

*Oct  5 13:13:16.503: Se1/0 CHAP: O SUCCESS id 2 len 4

*Oct  5 13:13:16.507: Se1/0 PPP: Sent CDPCP AUTHOR Request

R1(config-if)#

*Oct  5 13:13:16.515: Se1/0 CDPCP: Received AAA AUTHOR Response PASS

*Oct  5 13:13:16.543: Se1/0 PPP: Sent IPCP AUTHOR Request

>>>>>R2<<<<<<

R2(config-if)#no shut

R2(config-if)#shut

R2(config-if)#

*Oct  5 13:13:10.595: %LINK-5-CHANGED: Interface Serial1/0, changed state to administratively down

R2(config-if)#

R2(config-if)#

*Oct  5 13:13:10.595: %ENTITY_ALARM-6-INFO: ASSERT INFO Se1/0 Physical Port Administrative State Down

*Oct  5 13:13:11.595: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/0, changed state to down

R2(config-if)#no shut

R2(config-if)#

*Oct  5 13:13:15.631: %LINK-3-UPDOWN: Interface Serial1/0, changed state to up

*Oct  5 13:13:15.631: %ENTITY_ALARM-6-INFO: CLEAR INFO Se1/0 Physical Port Administrative State Down

R2(config-if)#

*Oct  5 13:13:15.635: Se1/0 PPP: Using default call direction

*Oct  5 13:13:15.639: Se1/0 PPP: Treating connection as a dedicated line

*Oct  5 13:13:15.639: Se1/0 PPP: Session handle[D5000002] Session id[2]

*Oct  5 13:13:15.639: Se1/0 PPP: Authorization required

*Oct  5 13:13:15.703: Se1/0 PPP: No authorization without authentication

*Oct  5 13:13:15.735: Se1/0 CHAP: I CHALLENGE id 2 len 23 from "R1"

*Oct  5 13:13:15.739: Se1/0 CHAP: Using hostname from unknown source

*Oct  5 13:13:15.739: Se1/0 CHAP: Using password from AAA

*Oct  5 13:13:15.739: Se1/0 CHAP: O RESPONSE id 2 len 23 from "R2"

*Oct  5 13:13:15.795: Se1/0 CHAP: I SUCCESS id 2 len 4

R2(config-if)#

*Oct  5 13:13:16.795: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/0, changed state to up

[cadet alain · Accepted solution]

Hi,

https://learningnetwork.cisco.com/thread/33576

Regards.

Alain

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[Roopak Sethi]

Hi Sir,

It means the router with "PPP authentication chap callin" command  will raise the challenge..

But what about the cisco document ??? Is it wrong.??

[cadet alain]

Hi,

sometimes Cisco docs have some wrong infos or the info is outdated or not pertaining to some cases or simply badly worded.But I can't say which case this is here.

I think that what counts is the real operation you observe when labbing.

Regards.

Alain

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[Roopak Sethi]

I got my answer

Thanks Sir...