单项选择题 Which of the following allows a technician to mask a private network of IP addresses behind onepublic IP address?（）

单项选择题 An administrator finds a phone line but does not know where the line goes or if it is active. Whichof the following can be used to test if it is active?（）

单项选择题 Which of the following devices would allow a technician using a packet sniffer to view all the dataon a network?（）