Wireshark Network Boundaries

This might be a stupid question but I have a capture file and need to identify the network boundary between a private LAN and public IP addresses.

Does wireahrk display the conversations in a way that the private source address is a gateway when communicating with a public IP address or is the source address potentially a host address within the private network and just doesn't show the gateway address.

I believe the gateway address to be 192.168.1.200 as it is the only IP address listed as having conversations with public IP addresses.

Is this a logical conclusion or should i be considering 192.168.1.254 as the gateway because DNS requests are sent to here and it is a more logical address for the gateway of a private LAN.

Regards

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