Huawei Updated H12-711_V4.0 Exam Questions and Answers by vincenzo

Explanation From HCIA-Security documents:

A SYN flood attack exploits the TCP three-way handshake mechanism by sending a large number of SYN packets without completing the handshake, causing the server or firewall to maintain excessive half-open connections and exhaust resources. Huawei firewalls provide multiple defense mechanisms at the TCP protocol level to mitigate this threat.

First, limiting the TCP connection establishment rate restricts how many new SYN requests are processed per second, preventing abnormal surges from consuming system resources. Second, limiting the number of half-open TCP connections ensures that the firewall does not allocate excessive memory and session table entries for incomplete handshakes, thereby protecting against resource exhaustion. Third, SYN cookie technology allows the firewall to avoid storing connection state information until the handshake is properly completed, effectively resisting SYN flood attacks without consuming large amounts of memory.

Interzone security policies primarily control traffic access based on zones and rules; they are not specifically designed as a SYN flood defense mechanism. Therefore, A, B, and C are correct.

The correct operation is D because email attachments are a common carrier for malware, phishing payloads, ransomware, Trojans, and malicious scripts. In enterprise security practice, a user should not trust an attachment only because the message looks work-related or appears to come from a company mailbox . Attackers can spoof sender information, disguise malicious content, or compromise legitimate accounts. Therefore, simply checking the content or sender is not enough to ensure safety.

A safer process is to verify the sender and the email details carefully , such as the address, subject, wording, unexpected urgency, and whether the attachment type matches the business context. After that, the attachment should be scanned with antivirus or endpoint security software before opening or saving it. This helps detect known malicious files and reduces the chance of infecting the host or internal network.

Option A is unsafe because work relevance alone does not prove the file is harmless. B is clearly wrong because attachments can directly affect information security. C is also unsafe because internal-looking mail can still be malicious. Therefore, D is the correct answer.