Which ICMP technique queries the subnet mask from the target?

Which ICMP technique queries the subnet mask from the target?

• A. IP protocol ping
• B. ICMP address mask ping
• C. TCP SYN ping
• D. ICMP timestamp ping

Answer: (B)

The idea being tested is how ICMP messages can reveal network configuration details. Asking for the subnet mask is done with an ICMP Address Mask Request, which is a specific ICMP message designed to elicit the subnet mask from the target. If the device supports this, it replies with the Address Mask Reply containing the mask (for example, 255.255.255.0). This is different from a standard ping, which uses an ICMP Echo Request to check reachability and does not disclose the mask. It’s also different from an ICMP timestamp ping, which returns timing information, and from a TCP SYN probe, which operates at the transport layer and doesn’t use ICMP at all. So the technique that queries the subnet mask is ICMP address mask ping.

The idea being tested is how ICMP messages can reveal network configuration details. Asking for the subnet mask is done with an ICMP Address Mask Request, which is a specific ICMP message designed to elicit the subnet mask from the target. If the device supports this, it replies with the Address Mask Reply containing the mask (for example, 255.255.255.0). This is different from a standard ping, which uses an ICMP Echo Request to check reachability and does not disclose the mask. It’s also different from an ICMP timestamp ping, which returns timing information, and from a TCP SYN probe, which operates at the transport layer and doesn’t use ICMP at all. So the technique that queries the subnet mask is ICMP address mask ping.