The correct answer is B. tcpdump. According to the CompTIA Network+ N10-009 objectives, troubleshooting network connectivity often requires validating whether traffic is actually reaching a device. tcpdump is a command-line packet analyzer that captures and displays packets being transmitted or received on a network interface in real time. This makes it the most effective tool among the options for verifying whether a server is receiving network traffic.
When using tcpdump, a technician can observe incoming packets, identify source and destination IP addresses, check protocols, and determine whether expected traffic (such as HTTP, ICMP, or DNS) is reaching the server. This directly helps isolate issues such as firewall blocking, routing problems, or application-layer failures.
The other options serve different purposes. traceroute is used to identify the path packets take across a network and diagnose routing issues, but it does not confirm packet arrival at the server interface. nslookup is used to query DNS servers for name resolution and is unrelated to packet capture. arp is used to view or manipulate the Address Resolution Protocol table, which maps IP addresses to MAC addresses, but it does not show live traffic flow.
Therefore, tcpdump is the most appropriate tool for confirming whether the server is receiving network traffic.
