1. Prepared By: Dr. Mohamed Abdeldayem Reference: Chapter 24 Wade Edwards, CCNP Complete Study Guide, 2005. Experiment 12 Configuring PPP on a serial link and configuring Password Authentication Protocol (PAP) and Challenge Handshake Authentication Protocol (CHAP) 1

2. The Objective of the Experiment Configuring PPP on a serial link and configuring Password Authentication Protocol (PAP) and Challenge Handshake Authentication Protocol (CHAP). 2

3. Configuring PPP on a serial link 3 The benefits of using PPP (RFC 1661 ) are that it is universal and efficient. PPP on Windows should be able to communicate with PPP on any access server, and the configuration demands on the client side are extremely small. Dedicated or Interactive PPP use the async mode dedicated command with the async mode interactive command Interface Addressing Options for Local Devices Static IP addressing Dynamic IP addressing (DHCP)

4. Configuring PPP on a serial link 4 An entire configuration file for DHCP services is shown here: service dhcp ip dhcp database ftp://dhcp:cisco@10.11.1.10/dhcp ip dhcp pool 0 network 10.10.1.0 /24 default-router 10.10.1.1 domain-name foo.com dns-server 10.2.20.51 netbios-name-server 10.2.20.51

5. configuring Password Authentication Protocol (PAP) 5 Password Authentication Protocol (PAP) provides basic security authentication for connections. The username and password information, however, are transmitted in cleartext, which can be intercepted by a hacker to compromise the network. PAP operates by establishing a connection and then checking the username and password information. If the username and password information matches, an OK message is returned and the session is allowed to proceed. To configure PAP, the administrator needs to configure both the service and a database of usernames and passwords. Using the following commands encapsulation ppp ppp authentication {chap | chap pap | pap chap | pap} [if-needed] [list-name | default] [callin] Usernames and passwords are added to the router with the username name password secret command.

6. Configuring Challenge Handshake Authentication Protocol (CHAP) 6 The following commands are used to enable PPP, a requirement for CHAP, and to configure the router for CHAP authentication: encapsulation ppp ppp authentication {chap | chap pap | pap chap | pap} [if-needed] [list-name | default] [callin]

7. Reference 7  Wade Edwards, CCNP Complete Study Guide, 2005.