Datasheet

Lab – Configuring Basic PPP with Authentication

.Jun 20 04:25:02.143: Se0/0/1 CDPCP: I CONFACK [ACKsent] id 1 len 4

.Jun 20 04:25:02.143: Se0/0/1 CDPCP: Event[Receive ConfAck] State[ACKsent to Open]

.Jun 20 04:25:02.155: Se0/0/1 IPCP: State is Open

.Jun 20 04:25:02.155: Se0/0/1 CDPCP: State is Open

.Jun 20 04:25:02.155: Se0/0/1 Added to neighbor route AVL tree: topoid 0, address

10.2.2.2

.Jun 20 04:25:02.155: Se0/0/1 IPCP: Install route to 10.2.2.2

.Jun 20 04:25:02.155: Se0/0/1 PPP: O pkt type 0x0021, datagramsize 80

.Jun 20 04:25:02.155: Se0/0/1 PPP: I pkt type 0x0021, datagramsize 80 link[ip]

.Jun 20 04:25:02.155: Se0/0/1 PPP: O pkt type 0x0021, datagramsize 84

.Jun 20 04:25:02.167: Se0/0/1 PPP: I pkt type 0x0021, datagramsize 84 link[ip]

.Jun 20 04:25:02.167: Se0/0/1 PPP: O pkt type 0x0021, datagramsize 68

.Jun 20 04:25:02.171: Se0/0/1 PPP: I pkt type 0x0021, datagramsize 68 link[ip]

.Jun 20 04:25:02.171: Se0/0/1 PPP: O pkt type 0x0021, datagramsize 148

.Jun 20 04:25:02.191: Se0/0/1 PPP: I pkt type 0x0021, datagramsize 148 link[ip]

.Jun 20 04:25:02.191: %OSPF-5-ADJCHG: Process 1, Nbr 209.165.200.225 on Serial0/0/1

from LOADING to FULL, Loading Done

.Jun 20 04:25:02.191: Se0/0/1 PPP: O pkt type 0x0021, datagramsize 68

.Jun 20 04:25:02.571: Se0/0/1 PPP: O pkt type 0x0021, datagramsize 80

.Jun 20 04:25:03.155: Se0/0/1 PPP: I pkt type 0x0207, datagramsize 333 link[cdp]

.Jun 20 04:25:03.155: Se0/0/1 PPP: O pkt type 0x0207, datagramsize 339

.Jun 20 04:25:04.155: Se0/0/1 PPP: O pkt type 0x0207, datagramsize 339

From the PPP debug messages, what phases did the Branch3 router go through before the link is up with

the Central router?

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PPP goes through the following phases: DOWN, ESTABLISHING, AUTHENTICATING, and UP.

e. Issue the debug ppp authentication command to observe the CHAP authentication messages on the

Central router.

Central# debug ppp authentication

PPP authentication debugging is on

f. Configure CHAP authentication on S0/0/1 on the Central router.

Central(config)# interface s0/0/1

Central(config-if)# ppp authentication chap

g. Observe the debug PPP messages relating to CHAP authentication on the Central router.

Central(config-if)#

.Jun 20 05:05:16.057: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/1,

changed state to down

.Jun 20 05:05:16.061: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.3.1 on Serial0/0/1 from

FULL to DOWN, Neighbor Down: Interface down or detached

.Jun 20 05:05:16.061: Se0/0/1 PPP: Using default call direction

.Jun 20 05:05:16.061: Se0/0/1 PPP: Treating connection as a dedicated line

.Jun 20 05:05:16.061: Se0/0/1 PPP: Session handle[12000078] Session id[112]

.Jun 20 05:05:16.081: Se0/0/1 CHAP: O CHALLENGE id 1 len 28 from "Central"

.Jun 20 05:05:16.089: Se0/0/1 CHAP: I CHALLENGE id 1 len 28 from "Branch3"

.Jun 20 05:05:16.089: Se0/0/1 PPP: Sent CHAP SENDAUTH Request