单项选择题 A user states that a networked printer is not working today, but yesterday the printer worked fine. The technician checks the user’s print queue and sees several jobs in the queue. The queue is flushed, restarted, and the user is still having the same issue. Which of the following should be verified NEXT on the printer? （）

单项选择题 Which of the following commands will allow a user to discover their IP address, subnet, and DNS?（）

单项选择题 Which of the following allows a program or port through a software firewall?（）