Which ARP-based technique is used to discover active devices on an IPv4 network?

Which ARP-based technique is used to discover active devices on an IPv4 network?

• A. ARP ping scan
• B. DNS enumeration
• C. ICMP echo scan
• D. Nmap stealth scan

Answer: (A)

On IPv4 networks, discovering which devices are active uses how the local network discovers who owns which IP. An ARP-based host discovery sends ARP requests for every IP in the target range, asking who has that IP and telling the requester to send back the MAC address. If a device owns that IP, it replies with its MAC, confirming that host is online. This ARP ping approach works at the Data Link layer and relies on broadcasts on the local subnet, so it’s fast and effective even when higher-layer probes (like ICMP) are blocked. That’s why the ARP-based ping method is the best fit for identifying active devices on an IPv4 network. DNS enumeration looks up names and records in the DNS system, not whether hosts are present on the local LAN. An ICMP echo scan uses pings at the IP layer, which can be blocked by firewalls and doesn’t use ARP. A general Nmap stealth scan is a broader technique that isn’t specifically ARP-based.

On IPv4 networks, discovering which devices are active uses how the local network discovers who owns which IP. An ARP-based host discovery sends ARP requests for every IP in the target range, asking who has that IP and telling the requester to send back the MAC address. If a device owns that IP, it replies with its MAC, confirming that host is online. This ARP ping approach works at the Data Link layer and relies on broadcasts on the local subnet, so it’s fast and effective even when higher-layer probes (like ICMP) are blocked. That’s why the ARP-based ping method is the best fit for identifying active devices on an IPv4 network.

DNS enumeration looks up names and records in the DNS system, not whether hosts are present on the local LAN. An ICMP echo scan uses pings at the IP layer, which can be blocked by firewalls and doesn’t use ARP. A general Nmap stealth scan is a broader technique that isn’t specifically ARP-based.