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PPP 协议 点到点协议. 深圳职业技术学院计算机系网络专业. 教学目标( Objectives ). 1. PPP 组成( PPP Components ) 2. PPP 会话建立( PPP Session Establishment ) 3. PPP 认证( PPP Authentication ) 4. PAP 和 CHAP 配置( Configure CHAP and PAP ) 5. 验证 PPP ( Verify PPP configuration ). 广域网连接类型:第一层 ( WAN Connection Types: Layer 1 ).
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PPP协议点到点协议 深圳职业技术学院计算机系网络专业
教学目标( Objectives) • 1. PPP组成(PPP Components) • 2.PPP会话建立( PPP Session Establishment) • 3. PPP认证( PPP Authentication) • 4.PAP和CHAP配置( Configure CHAPand PAP) • 5.验证PPP(Verify PPP configuration)
广域网连接类型:第一层(WAN Connection Types: Layer 1) 同步串行线路(Synchronous serial) 专线 Leased Line 异步串行线路 Asynchronous serial, ISDN Layer 1 Telephone Company 电路交换 Circuit-switched Synchronous serial 分组交换 Packet-switched Service Provider
串行线路点到点连接(Serial Point-to-Point Connections) Router connections End user device DTE CSU/DSU DCE Service Provider EIA/TIA-232 EIA/TIA-449 V.35 X.21 EIA-530
第二层典型的广域网封装协议(Typical WAN Encapsulation Protocols: Layer 2) HDLC, PPP, SLIP 专线 (Leased Line) X.25, Frame Relay, ATM 包交换 (Packet-switched) Service Provider PPP, SLIP, HDLC 电路交换 (Circuit-switched) Telephone Company
HDLC命令( HDLC Command) Router(config-if)#encapsulation hdlc • HDLC是串行线路的默认封装 • HDLC is the default encapsulation on synchronous serial interfaces
PPP组成(PPP Components) • 1. HDLC • PPP用HDLC作为点到点链路上基本的封装方法. • PPP uses (HDLC) as a basis for encapsulating datagrams over point-to-point links. • 2. LCP • 建立、配置和测试数据链路的连接 • Establishing, configuring, and testing the data-link connection. • 3. NCP • 建立和配置不同的网络层协议 • Establishing and configuring different network-layer protocols.
PPP组成(PPP Components) Multiple protocol encapsulations using NCPs in PPP • PPP用NCP进行多种协议的封装 • PPP can carry packets from several protocol suites using Network Control Programs • PPP用LCP进行链路的建立与控制 • PPP controls the setup of several link options using LCP PPP Encapsulation TCP/IP Novell IPX AppleTalk Link setup and control using LCP in PPP
PPP各层元素(Layering PPP Elements) IP IPX Layer 3 Protocols Network Layer IPCP IPXCP Many Others 网络控制协议(Network Control Protocol) PPP Data Link Layer Authentication, other options 链路控制协议(Link Control Protocol) Synchronous or Asynchronous 物理介质(Physical Media) Physical Layer
PPP会话建立(PPP Session Establishment) • 1. 链路的建立和配置的协商 • Link establishment and configuration negotiation • 2.链路质量检测 • Link-quality determination • 3.网络层协议配置协调 • Network-layer protocol configuration negotiation • 4.链路终止 • Link termination
PPP验证协议--PAP(PPP Authentication Protocol---PAP) PAP :Password Authentication Protocol PAP 2-Way Handshake Remote Router (SantaCruz) Central-Site Router (HQ) “santacruz, boardwalk” Accept/Reject • 密码明文传输 • Passwords sent in clear text • 对方控制连接请求 • Peer in control of attempts username santacruz password boardwalk Hostname: santacruz Password: boardwalk
PPP验证协议--CHAP(PPP Authentication Protocol---CHAP) CHAP :Challenge Handshake Authentication Protocol CHAP 3-Way Handshake Remote Router (SantaCruz) Central-Site Router (HQ) Challenge Response • 密文方式传递密码 • Use “secret” known only to authenticator and peer • 有效避免再生攻击和尝试攻击 • Avoiding playback or repeated trial-and-error attacks Accept/Reject username santacruz password boardwalk Hostname: santacruz Password: boardwalk
配置PPP(Configuring PPP) Router(config-if)#encapsulation ppp • 在端口模式下启动PPP • Enable PPP encapsulation
配置PPP认证(Configuring PPP Authentication) Router(config)#hostname name • 指定你自己路由器的主机名 • Assigns a host name to your router Router(config)#username name password password • 确认被认证路由器的用户名和密码 • Identifies the username and password of uthenticating router
配置PPP认证(Configuring PPP Authentication) Router(config-if)#ppp authentication{chap | chap pap | pap chap | pap} • 选择PAP还是CHAP作为认证协议 • Enables PAP and/or CHAP authentication
hostname left username right password sameone ! int serial 0/0 ip address 10.0.1.1 255.255.255.0 encapsulation ppp ppp authentication CHAP 配置CHAP实例(Configuring CHAP Example) Leftrouter Right router PSTN/ISDN hostname right username left password sameone ! int serial 0/0 ip address 10.0.1.2 255.255.255.0 encapsulation ppp ppp authentication CHAP 注意:用户名是对方的,密码一定要相同 区分大小写
4d20h: %LINK-3-UPDOWN: Interface Serial0, changed state to up 4d20h: Se0 PPP: Treating connection as a dedicated line 4d20h: Se0 PPP: Phase is AUTHENTICATING, by both 4d20h: Se0 CHAP: O CHALLENGE id 2 len 28 from ”left" 4d20h: Se0 CHAP: I CHALLENGE id 3 len 28 from ”right" 4d20h: Se0 CHAP: O RESPONSE id 3 len 28 from ”left" 4d20h: Se0 CHAP: I RESPONSE id 2 len 28 from ”right" 4d20h: Se0 CHAP: O SUCCESS id 2 len 4 4d20h: Se0 CHAP: I SUCCESS id 3 len 4 4d20h: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0, changed state to up 验证PPP认证(Verifying PPP Authentication) Service Provider Leftrouter Right router debug ppp authentication successful CHAP output
hostname left ! int serial 0/0 ip address 10.0.1.1 255.255.255.0 encapsulation ppp ppp pap sent-username left password cisco 配置PAP实例(Configuring PAP Example) Leftrouter Right router PSTN/ISDN hostname right username left password cisco ! int serial 0/0 ip address 10.0.1.2 255.255.255.0 encapsulation ppp ppp authentication pap 注意:用户名是对方的,密码一定要相同 区分大小写
思考题(Questions) • 1.什么是PPP?PPP由哪3部分组成? • 2.PPP的两种认证方法是什么?各有什么特点? • 3.PAP采用几次握手?CHAP采用几次握手?