Router Configuration<12>
PPP PAP认证
Target:
实验目的:
掌握PPP PAP认证的过程及配置
实验设备:
路由器（带串口） 2台
V.35线缆（DTE/DCE） 1对
实验原理:
PPP协议位于OSI七层模型的数据链路层，PPP协议按照功能划分为两个子层：LCP、NCP。LCP主要负责链路的协商、建立、回拨、认证、数据的压缩、多链路捆绑等功能。NCP主要负责和上层的协议进行协商，为网络层协议提供服务。
PPP的认证功能是指在建立PPP链路的过程中进行密码的验证，验证通过建立连接，验证不通过拆除链路。
PPP协议支持两种认证方式PAP和CHAP。PAP（Password Authentication Protocol，密码验证协议）是指验证双方通过两次握手完成验证过程，它是一种用于对试图登录到点对点协议服务器上的用户进行身份验证的方法。由被验证方主动发出验证请求，包含了验证的用户名和密码。由验证方验证后做出回复，通过验证或验证失败。在验证过程中用户名和密码以明文的方式在链路上传输。
实验拓扑图：
Step：
第一步：路由器基本配置
Router(config)#hostname Router A
Router A(config)#interface serial 4/0
Router A(config-if)#ip address 172.16.2.1 255.255.255.0
Router A(config-if)# encapsulation ppp
Router(config)#hostname Router B
Router B(config)#interface serial 4/0
Router B(config-if)#ip address 172.16.2.2 255.255.255.0
Router B(config-if)#encapsulation ppp
第二步：配置PAP认证
Router A(config)#interface serial 4/0
Router A(config-if)#ppp pap sent-username RouterA password 0 123
Router B(config)#username RouterA password 123
Router B(config)#interface serial 4/0
Router B(config-if)#ppp authentication pap
第三步：验证PAP认证
Router A#show interfaces serial 4/0
Index(dec):1 (hex):1
serial 4/0 is UP , line protocol is UP
Hardware is Infineon DSCC4 PEB20534 H-10 serial
Interface address is: 172.16.2.1/24
MTU 1500 bytes, BW 2000 Kbit
Encapsulation protocol is PPP, loopback not set
Keepalive interval is 10 sec , set
Carrier delay is 2 sec
RXload is 1 ,Txload is 1
LCP Open
Open: ipcp
Queueing strategy: WFQ
11421118 carrier transitions
V35 DCE cable
DCD=up DSR=up DTR=up RTS=up CTS=up
5 minutes input rate 54 bits/sec, 0 packets/sec
5 minutes output rate 46 bits/sec, 0 packets/sec
677 packets input, 14796 bytes, 0 no buffer, 28 dropped
Received 68 broadcasts, 0 runts, 0 giants
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 abort
655 packets output, 11719 bytes, 0 underruns , 5 dropped
0 output errors, 0 collisions, 18 interface resets
使用debug ppp authentication 命令验证配置。
Router B#debug ppp authentication
Router B#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Router B(config)#interface serial 4/0
Router B(config-if)#shutdown
Router B(config-if)#Sep 1 23:33:37 RouterB %7:%LINK CHANGED: Interface serial 4/0, changed state to administratively down
Sep 1 23:33:37 RouterB %7:%LINE PROTOCOL CHANGE: Interface serial 4/0, changed state to DOWN
Router B(config-if)#no shutdown
Router B(config-if)#Sep 1 23:33:43 RouterB %7:PPP: ppp_clear_author(), protocol = LCP
Sep 1 23:33:43 RouterB %7:%LINK CHANGED: Interface serial 4/0, changed state to up
Sep 1 23:33:45 RouterB %7:PPP: serial 4/0 [I] PAP-REQ id 2 len 12
Sep 1 23:33:45 RouterB %7:PPP: Authenticating peer serial 4/0
Sep 1 23:33:45 RouterB %7:PPP: serial 4/0 PAP authentication OK!
Sep 1 23:33:45 RouterB %7:PPP: serial 4/0 [O] PAP SUCCESS id 2 len 1
Sep 1 23:33:45 RouterB %7::PPP: serial 4/0 authentication OK, begin networkphase!
Sep 1 23:33:45 RouterB %7:PPP: ppp_clear_author(), protocol = IPCP
Sep 1 23:33:46 RouterB %7:%LINE PROTOCOL CHANGE: Interface serial 4/0, changed state to UP
【注意事项】
封装广域网协议时，要求V.35线缆的两个端口封装协议一致，否则无法建立链路。
【参考配置】
Router A#show running-config
Building configuration...
Current configuration : 593 bytes
!
version RGNOS 10.1.00(4), Release(18443)(Tue Jul 17 21:16:17 CST 2007 -ubu1server)
hostname Router A
!
interface serial 4/0
encapsulation PPP
ppp pap sent-username RouterA password 7 001b7210
ip address 172.16.2.1 255.255.255.0
clock rate 64000
!
interface serial 4/1
clock rate 64000
!
interface GigabitEthernet 0/0
duplex auto
speed auto
!
interface GigabitEthernet 0/1
duplex auto
speed auto
!
line con 0
line aux 0
line vty 0 4
login
!
end
Router B#show running-config
Building configuration...
Current configuration : 580 bytes
!
version RGNOS 10.1.00(4), Release(18443)(Tue Jul 17 21:16:17 CST 2007 -ubu1server)
hostname Router B
!
username RouterA password 0 123
!
interface serial 4/0
encapsulation PPP
ppp authentication pap
ip address 172.16.2.2 255.255.255.0
!
interface serial 4/1
clock rate 64000
!
interface GigabitEthernet 0/0
duplex auto
speed auto
!
interface GigabitEthernet 0/1
duplex auto
speed auto
!
line con 0
line aux 0
line vty 0 4
login
!
end