The anti-virus feature configured on the Huawei USG6000 product does not take effect. Which of the following are the possible reasons? (multiple choice)

In the anti-virus policy configuration of Huawei USG6000 product, what are the response methods of HTTP protocol? (multiple choice)

Buffer overflows, Trojan horses, and backdoor attacks are all attacks at the application layer.

Which of the following are true about the description of keywords? (Multiple Choices)

UDP is a connectionless protocol. UDP Flood attacks that change sources and ports will cause performance degradation of network devices that rely on session forwarding.
Even the session table is exhausted, causing the network to be paralyzed. Which of the following options is not a preventive measure for UDP Flood attacks?