Which defense is described as preventing an ICMP flood DDoS attack by blocking ping requests?

• A. Preventing an ICMP flood DDoS attack
• B. Authentication
• C. Secure passwords
• D. Authorization

Answer: (A)

Blocking ICMP echo requests is a direct defense against an ICMP flood DDoS because it targets the same traffic that the attack relies on. An ICMP flood floods a target with a large volume of ICMP packets (often Echo Requests), overwhelming bandwidth and processing resources. By dropping or rate-limiting those Echo Request messages at the network edge (firewall or router), that flood traffic is prevented from reaching the host, helping preserve availability. In practice, this means implementing rules to block or throttle ICMP Echo traffic while ideally allowing other vital traffic to pass. It’s a trade-off, since some legitimate diagnostic ping traffic may be affected, which can be mitigated with selective or per-source rate limiting. The other concepts—authentication, secure passwords, and authorization—deal with verifying who can access resources and granting permissions, not with filtering or controlling traffic flows, so they don’t prevent an ICMP flood attack.