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sybex ccna fast pass 3rd edition 2007 phần 9

, sản lượng sẽ giống như thế này:PPP với CHAP xác thực là một chứng thực ba chiều, và nếu tên người dùng và mật khẩu khôngxác thực yêu cầu, có một mật khẩu và ID, các bộ định tuyến địa phương khi cố gắng kết nối. Không giống như an toàn hơn CHAP (Challenge Handshake Authentication Protocol), | 374 Chapter 8 Implement and verify WAN links 1d16h Se0 0 CHAP O RESPONSE id 208 len 27 from Pod1R1 1d16h Se0 0 CHAP I RESPONSE id 219 len 27 from Pod1R2 1d16h Se0 0 CHAP O SUCCESS id 219 len 4 1d16h Se0 0 CHAP I SUCCESS id 208 len 4 But if you have the username wrong as we did previously in the PPP authentication failure example back in Figure 14.11 the output would look something like this 1d16h Se0 0 PPP Using default call direction 1d16h Se0 0 PPP Treating connection as a dedicated line 1d16h SYS-5-CONFIG_I Configured from console by console 1d16h Se0 0 CHAP O CHALLENGE id 220 len 27 from Pod1R1 1d16h Se0 0 CHAP I CHALLENGE id 209 len 27 from Pod1R2 1d16h Se0 0 CHAP O RESPONSE id 209 len 27 from Pod1R1 1d16h Se0 0 CHAP I RESPONSE id 220 len 27 from Pod1R2 1d16h Se0 0 CHAP O FAILURE id 220 len 25 msg is MD DES compare failed PPP with CHAP authentication is a three-way authentication and if the username and passwords are not configured exactly the way they should be then the authentication will fail and the link will be down. Exam Objectives Remember the PPP Data Link layer protocols. The three Data Link layer protocols are Network Control Protocol NCP which defines the Network layer protocols Link Control Protocol LCP a method of establishing configuring maintaining and terminating the point-to-point connection and High-Level Data Link Control HDLC the MAC layer protocol that encapsulates the packets. Review Questions 375 Review Questions 1. Which command will display the CHAP authentication process as it occurs between two routers in the network A. show chap authentication B. show interface serial 0 C. debug ppp authentication D. debug chap authentication 2. Suppose that you have a customer who has a central HQ and six branch offices. They anticipate adding six more branches in the near future. They wish to implement a WAN technology that will allow the branches to economically connect to HQ and you have no free ports on the HQ router. Which of the following .