配置PPP PAP 认证：

1. 单向认证：R1启动pap R1为主验证方，R2为被验证方。

r1(config)#inter s1/0

r1(config-if)#ip add 202.146.0.1 255.255.255.0

r1(config-if)#no shutdown

r1(config-if)#encapsulation ppp

r1(config-if)#ppp authenticatin pap

r1(config-if)#exit

r1(config)#username cisco password cisco

r2(cinfig)#inter s1/0

r2(config-if)#ip add 202.146.0.2 255.255.255.0

r2(config-if)#no shutdwon

r2(config-if)#encapsulation ppp

r2(config-if)#ppp pap sent-username cisco password cisco

r2(config-if)#exit

2. 双向认证：R1和R2同时启动PAP.

r1上的配置：

Router>

Router>en

Router#config t

Router(config)#enable s cisco

Router(config)#line c 0

Router(config-line)#pass cisco

Router(config-line)#login

Router(config-line)#logging sy

Router(config-line)#no domain-lookup

Router(config-line)#exec-t 0 0

Router(config-line)#exit

Router(config)#line aux 0

Router(config-line)#pass cisco

Router(config-line)#login

Router(config-line)#line vty 0 903

Router(config-line)#pass cisco

Router(config-line)#login

Router(config-line)#exit

Router(config)#hostname r1

r1(config)#inter s1/0

r1(config-if)#ip add 202.146.0.1 255.255.255.0

r1(config-if)#n shutdown

r1(config-if)#encap

r1(config-if)#encapsulation ppp

r1(config-if)#ppp authentication pap

r1(config-if)#ppp pap sent-username cisco pass cisco

r1(config-if)#exit

r1(config)#username cisco password cisco

r2上的配置：

Router>en

Router#config t

Router(config)#enable s cisco

Router(config)#line c 0

Router(config-line)#pass cisco

Router(config-line)#login

Router(config-line)#logging sy

Router(config-line)#no domain-lookup

Router(config-line)#exec-t 0 0

Router(config-line)#exit

Router(config)#line aux 0

Router(config-line)#pass cisco

Router(config-line)#login

Router(config-line)#line vty 0 903

Router(config-line)#pass cisco

Router(config-line)#login

Router(config-line)#exit

Router(config)#hostname r2

r2(config)#inter s1/0

r2(config-if)#ip add 202.146.0.2 255.255.255.0

r2(config-if)#no shutdown

r2(config-if)#encapsulation ppp

r2(config-if)#ppp authentication pap

r2(config-if)#ppp pap sent-username cisco password cisco

r2(config-if)#exit

r2(config)#username cisco password cisco

r2(config)#end

r2#p 202.146.0.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 202.146.0.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 8/28/84 ms