单项选择题 A Stateful firewall is MOST useful in protecting against which of the following network scans?（）

多项选择题 By default, which of the following ports would a network need to have opened to allow for thetransmission of incoming and outgoing email?（） (Select TWO).

单项选择题 A technician receives an urgent call that the switch in accounting is down. Which of the followingshould the technician do FIRST to troubleshoot this issue?（）