Configuración ppp chap en doble sentido

Configuración de enlace serie con autenticación chap en doble sentido

En R1

Se crea un usuario para el router R2 con un password que "ha de ser igual en los dos lados del enlace"

username R2 password 0 PW

y configuramos la interfaz serial

interface Serial0/0
 ip address 10.0.0.1 255.255.255.252
 encapsulation ppp
 serial restart-delay 0
 ppp authentication chap
 ppp chap password 0 PW1
 ppp pap refuse
end

En R2
Configuramos un usuario y un password para R1 manteniendo el password

username R1 password 0 PW

y configuramos la interfaz serial

interface Serial0/0
 ip address 10.0.0.2 255.255.255.252
 encapsulation ppp
 serial restart-delay 0
 ppp authentication chap
 ppp chap password 0 PW1
 ppp pap refuse
end

y con el debug ppp authentication podemos ver el proceso que sigue para autenticar

*Mar  1 00:31:22.875: %SYS-5-CONFIG_I: Configured from console by console
*Mar  1 00:31:24.387: %LINK-3-UPDOWN: Interface Serial0/0, changed state to up
R1#
*Mar  1 00:31:24.387: Se0/0 PPP: Using default call direction
*Mar  1 00:31:24.391: Se0/0 PPP: Treating connection as a dedicated line
*Mar  1 00:31:24.391: Se0/0 PPP: Session handle[9400018B] Session id[399]
*Mar  1 00:31:24.391: Se0/0 PPP: Authorization required
*Mar  1 00:31:24.511: Se0/0 CHAP: O CHALLENGE id 142 len 23 from "R1"
*Mar  1 00:31:24.599: Se0/0 CHAP: I CHALLENGE id 142 len 23 from "R2"
*Mar  1 00:31:24.603: Se0/0 CHAP: I RESPONSE id 142 len 23 from "R2"
*Mar  1 00:31:24.607: Se0/0 PPP: Sent CHAP LOGIN Request
*Mar  1 00:31:24.607: Se0/0 CHAP: Using hostname from unknown source
*Mar  1 00:31:24.611: Se0/0 CHAP: Using password from AAA
R1#
*Mar  1 00:31:24.611: Se0/0 CHAP: O RESPONSE id 142 len 23 from "R1"
*Mar  1 00:31:24.615: Se0/0 PPP: Received LOGIN Response PASS
*Mar  1 00:31:24.619: Se0/0 PPP: Sent LCP AUTHOR Request
*Mar  1 00:31:24.619: Se0/0 PPP: Sent IPCP AUTHOR Request
*Mar  1 00:31:24.623: Se0/0 LCP: Received AAA AUTHOR Response PASS
*Mar  1 00:31:24.623: Se0/0 IPCP: Received AAA AUTHOR Response PASS
*Mar  1 00:31:24.627: Se0/0 CHAP: O SUCCESS id 142 len 4
*Mar  1 00:31:24.755: Se0/0 CHAP: I SUCCESS id 142 len 4
*Mar  1 00:31:24.759: Se0/0 PPP: Sent CDPCP AUTHOR Request
*Mar  1 00:31:24.759: Se0/0 PPP: Sent IPCP AUTHOR Request
*Mar  1 00:31:24.767: Se0/0 CDPCP: Received AAA AUTHOR Response PASS
R1#
*Mar  1 00:31:25.755: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed state to up