预配置第一步：在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)#no sh第二步:
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预配置
第一步：在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)#no sh
第二步: 在R2上的预配置
R2(config)#int s2/1
R2(config-if)#ip add 10.1.1.2 255.255.255.0
R2(config-if)#no sh
实验过程：
第一步：在R1上配置用户名与密码和PPP PAP认证
R1(config)#username R2 password cisco
R1(config)#int s1/2
R1(config-if)#ppp authentication PAP
R1(config-if)#ppp pap sent-username R1 password 0 cisco
R1(config-if)#^Z
R1#
第二步：在R2上配置用户名与密码和PPP PAP认证
R2(config)#username R1 password cisco
R2(config)#int s2/1
R2(config-if)#ppp authentication pap
R2(config-if)#ppp pap sent-username R2 password 0 cisco
R2(config-if)#^Z
R2#
第三步：在R1上调试PPP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)#
00:06:11: %LINK-5-CHANGED: Interface Serial1/2, changed state to administratively down
00:06:12: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/2, changed state to down
R1(config-if)#no sh
R1(config-if)#
00:06:19: %LINK-3-UPDOWN: Interface Serial1/2, changed state to up
R1(config-if)#
00:06:19: Se1/2 PPP: Treating connection as a dedicated line
00:06:19: Se1/2 PPP: Phase is AUTHENTICATING, by both
00:06:19: Se1/2 PAP: O AUTH-REQ id 3 len 13 from "R1"
00:06:19: Se1/2 PAP: I AUTH-REQ id 3 len 13 from "R2"
00:06:19: Se1/2 PAP: I AUTH-ACK id 3 len 5
00:06:19: Se1/2 PAP: Authenticating peer R2
00:06:19: Se1/2 PAP: O AUTH-ACK id 3 len 5 （通过认证）
R1(config-if)#
第四步：在R1上查看路由表是否学习到了对方的接口
R1#sh ip rout
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default
U - per-user static route, o - ODR
T - traffic engineered route
Gateway of last resort is not set
10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 10.1.1.2/32 is directly connected, Serial1/2
C 10.1.1.0/24 is directly connected, Serial1/2
