Which tool can be used to determine who terminated the call first in a 3CX system?

The correct choice is Wireshark, as it is a powerful network protocol analyzer that captures and analyzes the packets being transmitted over a network. Within the context of a 3CX system, Wireshark can monitor SIP (Session Initiation Protocol) messages, which are critical for establishing and managing voice calls. By analyzing the SIP messages captured during a call session, you can identify key events such as call initiation, continuation, and termination.

Specifically, Wireshark allows you to see the details of SIP INVITE, BYE, and other relevant messages, helping you determine which party sent the termination signal first. This capability is essential for troubleshooting call problems, such as identifying whether a call was dropped by the caller or the recipient, or if network issues disrupted the call.

While the other tools also have their purposes in network analysis, they do not specifically provide the focused functionality that Wireshark does in this scenario. TCPDump is a command-line packet capture tool which can capture SIP packets, but it lacks the user-friendly interface and filtering capabilities of Wireshark for detailed analysis. SIP Tester is mainly used for testing SIP functionality and doesn't primarily focus on call detail records. Traceroute helps in diagnosing routing paths but does not provide insights