单项选择题
What is a static packet-filtering firewall used for ？（）
A.It validates the fact that a packet is either a connection request or a data packet belonging to a connection
B.It evaluates network packets for valid data at the application layer before allowing connections
C.It analyzes network traffic at the network and transport protocol layers
D.It keeps track of the actual communication process through the use of a state table
点击查看答案&解析
相关考题
