Since I’ve been studying my WAN connection traffic behavior, I added rules to block any RFC 1918 trying to exit my WAN interface, and I’m logging them.
During the time my wife was doing a video chat on Whats App, it repeatedly tried to access a 192.168.x.x address that is not part of my network, so it tried to exit the gateway to the WAN. I say Whats App because that’s what she was doing during the time these packets were logged, confirmed by her call data. Could be something else I suppose but it would be coincidence.
I suspect it’s the local IP of the other end of the connection.
Why is it doing this? In case maybe I’m double natted and the other end of the connection is in the same house or close vicinity? The only way my end would know about this address is if it was sent by Whats App from the other side over the internet initially.