单项选择题
A. one-way
B. two-way
C. three-way
D. four-way
E. no handshakes required during authentication
F. None of the above
单项选择题 After attempting to telnet into a router, you are denied and you receive the error message "password required, but none set." What configuration changes will allow telnet access into this router?（）
单项选择题 Which wild card mask will enable a network administrator to permit access to the Internet for only hosts that are assigned an address in the range 192.168.8.0 through 192.168.15.255?（）
单项选择题 You are an administrator of a network that uses PPP for CHAP authentication over ever WAN link. What command would you enter to display the CHAP authentication as it occurs in real time?（）
