When viewing a Remote Extension via STUN in Wireshark, what IP address should appear in the "Contact" field?

In the scenario of viewing a Remote Extension via STUN in Wireshark, the "Contact" field should contain the local IP address of the remote phone. This is because the primary purpose of using STUN (Session Traversal Utilities for NAT) is to facilitate communication for devices behind a NAT (Network Address Translation) by allowing them to determine their public IP address and port number. However, in the context of SIP (Session Initiation Protocol) signaling, when a remote phone registers with the 3CX PBX, it does so utilizing its local IP address initially.

When the remote phone sends its registration message, it provides its internal (local) address in the "Contact" field so that the PBX can reach it directly. This registration process allows for proper NAT handling, ensuring that the PBX knows how to send media and signaling to the correct local address, which ultimately is essential for establishing successful communication.

The other options refer to various IP addresses that would not appear in the "Contact" field for a remote extension utilizing STUN. The public IP address of the 3CX would be the address that external parties use to communicate with the PBX, while the private IP address of the PBX is within the internal network and