预配置：第一步：R1上的预配置R1(config)#int s1/2R1(config-if)#ip add 10.1.1.1 255.255.255.0R1(config-if)#encapsula
.
预配置：
第一步：R1上的预配置
R1(config)#int s1/2
R1(config-if)#ip add 10.1.1.1 255.255.255.0
R1(config-if)#encapsulation ppp
R1(config-if)ppp authentication chap
R1(config-if)#no sh
第二步：R2的预配置
R2(config)#int s2/1
R2(config-if)#ip add 12.1.1.2 255.255.255.0
R2(config-if)#en
R2(config-if)#encapsulation ppp
R2(config-if)ppp authentication chap
R2(config-if)#no sh
实验过程:
第一步：在R1上配置用户名与密码和CHAP认证
R1(config)#
R1(config)#username R2 password bbb
R1(config)#int s1/2
R1(config-if)#ppp authentication chap
R1(config-if)#
第二步：在R2上配置用户名与密码和CHAP认证
R2(config)#username R1 password bbb
R2(config)#int s2/1
R2(config-if)#ppp authentication chap
R2(config-if)#
第三步：在R1上调试PPP CHAP认证过程
R1#debug ppp authentication
PPP authentication debugging is on
R1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#int s1/2
R1(config-if)#sh
R1(config-if)#
R1(config-if)#
00:07:23: %LINK-5-CHANGED: Interface Serial1/2, changed state to administratively down
00:07:24: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/2, changed state to down
R1(config-if)#no sh
R1(config-if)#
00:07:29: %LINK-3-UPDOWN: Interface Serial1/2, changed state to up
R1(config-if)#
00:07:29: Se1/2 PPP: Treating connection as a dedicated line
00:07:29: Se1/2 PPP: Phase is AUTHENTICATING, by both
00:07:29: Se1/2 CHAP: O CHALLENGE id 2 len 23 from "R1"
00:07:29: Se1/2 CHAP: I CHALLENGE id 3 len 23 from "R2"
00:07:29: Se1/2 CHAP: O RESPONSE id 3 len 23 from "R1"
00:07:29: Se1/2 CHAP: I RESPONSE id 2 len 23 from "R2"
00:07:29: Se1/2 CHAP: O SUCCESS id 2 len 4
00:07:29: Se1/2 CHAP: I SUCCESS id 3 len 4 （通过认证）
R1(config-if)#
00:07:30: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/2, changed state to up
R1(config-if)#
