How do you capture on a specific interface in Wireshark?

• A. Right-click a packet and choose cap on interface
• B. Start capture on that interface or use Capture → Options to select the interface
• C. Open the capture file and filter by IP address
• D. Use a display filter to limit to that interface

Answer: (B)

To capture on a specific interface, you must start a capture on that interface. In Wireshark, open the Capture options (Capture → Options) or the Capture Interfaces dialog, pick the desired network interface from the list, and start the capture. This sets the capture source to that interface so you collect only traffic from it.

Opening a capture file and applying a filter will only affect what you see after the capture is already done, not which interface is being captured. A display filter affects displayed packets, not the act of capturing. Similarly, trying to start a capture by right-clicking a packet isn’t how the capture process assigns an interface—captures start on the chosen interface before any packets are captured.