单项选择题 Which of the following commands should Mike, a technician, use to display the available switches of a command line utility?（）

单项选择题 A user has just moved a PC from one office to another. The patch cable and the NIC do notappear to be functioning in the new office but were working before the move. The patch cable is plugged in correctly to both the NIC and the wall jack. Which of the following actions should the technician take FIRST?（）

单项选择题 Which of the following default ports must be opened to allow a technician to telnet into a machine?（）