How to quickly test L3 reachability?

• A. Ping the remote host only
• B. Ping local gateway → next hop → remote host; traceroute for path divergence.
• C. Use ARP only
• D. Use netstat

Answer: (B)

Testing L3 reachability means confirming you can route packets to the remote IP and understanding the path they take. The fastest way to do this is to exercise the route from your local network through each hop and use a traceroute to see where the path may diverge. Start by pinging the local gateway to confirm the edge device is reachable, then ping the next hop to validate the route beyond the local network, and finally ping the remote host to verify end-to-end reachability. Running a traceroute along the way will show the actual path and highlight where the path deviates or where a hop fails, enabling quick diagnosis. Pinging only the remote host gives you end-to-end reachability but not where a problem lies. ARP checks operate at Layer 2 and don’t test L3 reachability, and netstat doesn’t verify reachability at all; it shows sockets and connections rather than path status.