Datasheet

Lab – Configuring Basic PPP with Authentication
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Central(config-if)# encapsulation ppp
Central(config-if)#
Jun 20 03:17:15.933: %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 03:17:17.933: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/1,
changed state to down
Jun 20 03:17:23.741: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/1,
changed state to up
Jun 20 03:17:23.825: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.3.1 on Serial0/0/1 from
LOADING to FULL, Loading Done
Branch3(config)# interface s0/0/1
Branch3(config-if)# encapsulation ppp
Branch3(config-if)#
Jun 20 03:17:21.744: %OSPF-5-ADJCHG: Process 1, Nbr 209.165.200.225 on Serial0/0/1
from FULL to DOWN, Neighbor Down: Interface down or detached
Jun 20 03:17:21.948: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/1,
changed state to down
.Jun 20 03:17:21.964: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/1,
changed state to up
.Jun 20 03:17:23.812: %OSPF-5-ADJCHG: Process 1, Nbr 209.165.200.225 on Serial0/0/1
from LOADING to FULL, Loading Done
m. Verify that end-to-end connectivity is restored before continuing to Part 3.
Part 3: Configure PPP CHAP Authentication
Step 1: Verify that PPP encapsulation is configured on all serial interfaces.
Record the command used to verify that PPP encapsulation is configured.
_______________________________________________________________________________________
show running-config with output modifiers or show interfaces interface-id
Step 2: Configure PPP CHAP authentication for the link between the Central router and the
Branch3 router.
a. Configure a username for CHAP authentication.
Central(config)# username Branch3 password cisco
Branch3(config)# username Central password cisco
b. Issue the debug ppp commands on the Branch3 router to observe the process, which is associated with
authentication.
Branch3# debug ppp negotiation
PPP protocol negotiation debugging is on
Branch3# debug ppp packet
PPP packet display debugging is on
c. Configure the interface S0/0/1 on Branch3 for CHAP authentication.
Branch3(config)# interface s0/0/1
Branch3(config-if)# ppp authentication chap
d. Examine the debug PPP messages on the Branch3 router during the negotiation with the Central router.