初始：配置各路由器的IP地址。
Router(config)#host r1
r1(config)#int s1/0
r1(config-if)#clock rate 64000
r1(config-if)#ip address 10.1.1.1 255.255.255.0
r1(config-if)#no sh
Router(config)#host r2
r2(config)#int s1/0
r2(config-if)#ip address 10.1.1.2 255.255.255.0
r2(config-if)#clock rate 64000
r2(config-if)#no sh
I：配置PAP单向身份验证
r1(config)#username r2 password 123 /验证方建立数据库
r1(config)#int s1/0
r1(config-if)#encapsulation ppp /进行PPP封装
r1(config-if)#ppp authentication pap /使用PAP实现PPP的验证
r2(config)#int s1/0
r2(config-if)#encapsulation ppp
r2(config-if)#ppp pap sent-username r2 password 123 /发送验证信息
测试结果：
r1#ping 10.1.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/9/16 ms
II：配置PAP双向身份验证
r1(config)#username r2 password 123
r1(config)#int s1/0
r1(config-if)#encapsulation ppp
r1(config-if)#ppp authentication pap
r1(config-if)#ppp pap sent-username r1 password 321 /注意此时发送的password
r2(config)#username r1 password 321
r2(config)#int s1/0
r2(config-if)#encapsulation ppp
r2(config-if)#ppp authentication pap
r2(config-if)#ppp pap sent-username r2 password 123 /注意此时发送的password
测试结果：
r1#ping 10.1.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/10/16 ms
III：配置CHAP单向的身份验证.
r1(config)#username r2 password 123
r1(config)#int s1/0
r1(config-if)#encapsulation ppp
r1(config-if)#ppp authentication chap
r2(config)#int s1/0
r2(config-if)# encapsulation ppp
r2(config-if)#ppp chap hostname r2
r2(config-if)#ppp chap password 123
测试结果：
r2#ping 10.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/18/36 ms
IV：配置CHAP双向的身份验证.
r1(config)#username r2 password 123
r1(config)#int s1/0
r1(config-if)# encapsulation ppp
r1(config-if)# ppp authentication chap
r2(config-if)#username r1 password 123
r2(config)#int s1/0
r2(config-if)# encapsulation ppp
r2(config-if)# ppp authentication chap
测试结果：
r2#ping 10.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/18/36 ms
