单项选择题 A small amount of spoofed packets are being sent across a network and a large amount of reply packets are being sent back to the network resource. Which of the following BEST describes this security threat?（）

单项选择题 Which of the following is a hybrid network topology used for fault tolerance, in which all computersMUST connect to each other?（）

单项选择题 An administrator replaced a router with a switch. End users are able to access network shares butare not able to access the Internet. Which of the following is the BEST explanation why the usersare unable to access the Internet?（）