单项选择题 Which of the following authentication protocols uses certificates to negotiate access to the network?（）

单项选择题 Which of the following tools is used to show the active routes on a workstation?（）

单项选择题 A network technician is troubleshooting a network issue that has just been reported. Which of thefollowing troubleshooting steps should the technician take FIRST to help resolve this issue?（）