PPP/PAP Configuration Issue.

[J. Diego Chacon M.]

Hello everyone,

I'm trying to set up a lab in GNS3 for PPP using PAP with some c7200 routers but if I use the command 'ppp authentication pap' on both routers, on R2 I get interface up/down and in R1 remains up/up.

If I only use the command on R1, everything shows up/up

Is this expected?

I have used a video by Kevin Wallace for CCNP Route 300-101 to set this up but i've been unable to do it.

Here is the config:

______________________
R1
config t
interface serial 4/0
ip address 10.1.1.1 255.255.255.252
encapsulation ppp
no shutdown
username papuser password pappass
interface serial 4/0
ppp authentication pap
______________________
R2
config t
interface serial 4/0
ip address 10.1.1.2 255.255.255.252
encapsulation ppp
no shutdown
ppp pap sent-username papuser password pappass
ppp authentication pap

[Mark Malone]

Hi

should you not have the ppp pap sent-username on R1 too under serial to complete both way authentication

[J. Diego Chacon M.]

Hi Mark,

Thanks for your answer. Do you mean that the command should not be on R2? It is not set on R1 anyway. Everything is working fine until I add the command "ppp authentication pap" to both routers.

[Kevin Rivest · Accepted solution]

What Mark means is, configure the PAP username and password sent and the username and password in the local database on both routers if you would like to perform PAP authentication in both directions. The following example shows what I mean:

R1

config t
interface serial 4/0
 ip address 10.1.1.1 255.255.255.252
 encapsulation ppp
 ppp pap sent-username papuser1 password pappass1
 ppp authentication pap
 no shutdown
username papuser2 password pappass2

R2

config t
interface serial 4/0
 ip address 10.1.1.2 255.255.255.252
 encapsulation ppp 
 ppp pap sent-username papuser2 password pappass2
 ppp authentication pap
 no shutdown
username papuser1 password pappass1

Hope that is clear and answers your question.

[J. Diego Chacon M.]

Clear enough! 

Thanks guys!

[bsapida]

I was doing tshoot on this too.. chap is succesfully connecting but when I rever back to pap, its failing.. adding "ppp pap username sent ..." does fix the issue. I just wish i saw this discussion earlier ;). but its all good, this is a good tshoot exercise. thanks for sharing

-Bien-