单项选择题
Which version of NTP was the first to support cryptographic authentication?（）
A.Version 1 B.Version 5 C.Version 4 D.Version 3
单项选择题 How does NTP help you troubleshoot network problems?（）
单项选择题 Which of the following can we draw from the given information concerning the class-map "all-traffic"?（）
单项选择题 Which one of these class maps was configured to match traffic for CS5?（）
