Which Windows command shows current TCP/UDP port usage on the machine?

• A. arp -a
• B. Netstat -na
• C. ipconfig
• D. tasklist

Answer: (B)

Netstat is the tool that reveals active network sockets, which is what “current TCP/UDP port usage” refers to. Using the numeric option keeps addresses and ports in numbers, and the all option includes both listening ports and active connections for both TCP and UDP. Netstat -na thus gives a complete, quick snapshot of what ports are open or in use on the machine and their states. If you ever need to know exactly which process owns a port, you can add the owning process flag (netstat -nao). The other commands don’t display port usage: arp -a shows the ARP table, ipconfig shows IP configuration, and tasklist lists processes.