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New Member

PPP username

Hi Experts,

If i have two routers(point-to-point), the first router hostname is R1 and the second router hostname is R2..

In configuring PPP username on R1:

username R2 password Cisco

In configuting ppp username on R2:

username R1 password Cisco

Can i change username R2 and username R1 in both routers configuration to be any name i want for example :

username R1 replace with username Linux

username R2 replace with username Lindows

suppose i have either CHAP or PAP


Ibrahim ALwahidi


Re: PPP username


You can freely do this, but keep in mind the way you are configuring PAP and CHAP:


The local router uses the username and password specified by the ppp pap sent-username command to authenticate itself to a remote device. The other router must have this same username/password configured using the username command described above.

Note: The function of the local username command for PAP is different than its function for CHAP. With CHAP, this username and password are used to generate the response to the challenge, but PAP only uses it to verify that an incoming username and password are valid.


By default, the router uses its hostname to identify itself to the peer. However, this CHAP username can be changed through the ppp chap hostname command.


Mohammed Mahmoud.

New Member

Re: PPP username

Thanx Mohammad for ur immediate response.

As i understand i can change the username in both PAP and CHAP by using special commands not by default.

But in default configuration i can't change the username ...



encap ppp

ppp authen pap

username X pass cisco



encap ppp

ppp authe pap

username R1 pass cisco

So i cant use X as username in R1 by default because it will lead to down line protocol of the serial interface.

2)As i understand form u in my previous question that both routers should have the same authentication method(CHAP or PAP) otherwise it will lead to down the line protocol of the seriail interface.


Ibrahim Alwahidi

Re: PPP username

Hi Ibrahim,

To make it simple, imagine the authentication as a client server issue, if the server is used to authenticate using PAP then the client must be configured to use PAP and the same for CHAP, thus you can have one side using PAP to authenticate the other and the other side using CHAP to authenticate the first side, put you'll end up having both PAP and CHAP configuration on both sides.


Mohammed Mahmoud.

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