Which tool would you deploy to watch for unusual ARP traffic as part of security monitoring?

Which tool would you deploy to watch for unusual ARP traffic as part of security monitoring?

• A. Netstat
• B. Tcpdump
• C. ARPwatch
• D. Nmap

Answer: (C)

Watching ARP traffic for anomalies is best done with a tool built to monitor and alert on IP-to-MAC mappings in real time. ARPwatch continuously observes ARP packets on the local network, maintains a live database of which IP is associated with which MAC, and quickly flags changes. If a host suddenly appears with a different MAC for the same IP or a new mapping shows up, ARPwatch raises an alert, which is exactly what you want for detecting ARP spoofing or man-in-the-middle attempts. Netstat is focused on current connections and routing information, not ARP traffic across the LAN. Tcpdump can capture ARP packets, but it’s a general packet sniffer that requires additional parsing and scripting to generate ongoing alerts. Nmap is a scanning tool used for discovering hosts and services, not for monitoring ongoing ARP behavior. ARPwatch, by contrast, is purpose-built for monitoring ARP activity and alerting on suspicious changes, making it the most suitable choice for security monitoring in this scenario.

Watching ARP traffic for anomalies is best done with a tool built to monitor and alert on IP-to-MAC mappings in real time. ARPwatch continuously observes ARP packets on the local network, maintains a live database of which IP is associated with which MAC, and quickly flags changes. If a host suddenly appears with a different MAC for the same IP or a new mapping shows up, ARPwatch raises an alert, which is exactly what you want for detecting ARP spoofing or man-in-the-middle attempts.

Netstat is focused on current connections and routing information, not ARP traffic across the LAN. Tcpdump can capture ARP packets, but it’s a general packet sniffer that requires additional parsing and scripting to generate ongoing alerts. Nmap is a scanning tool used for discovering hosts and services, not for monitoring ongoing ARP behavior. ARPwatch, by contrast, is purpose-built for monitoring ARP activity and alerting on suspicious changes, making it the most suitable choice for security monitoring in this scenario.