What does Proxy-ARP do?

• A. Answers ARP requests regardless of origin
• B. Forwards packets between VLANs
• C. Drops ARP requests from outside the subnet
• D. Reserves IP addresses

Answer: (A)

Proxy-ARP lets a router answer ARP requests on behalf of a host that isn’t on the local subnet. When a device on the LAN asks “who owns this IP?” and that IP is reachable through the router, the router responds with its own MAC address, so the traffic is sent to the router and then forwarded onward. That means ARP replies can come from the router regardless of which device on the LAN issued the request, which is exactly what this option describes. It’s not about inter-VLAN forwarding, nor about blocking ARP requests, nor about reserving IPs.