How do I send data across WAN networks in Python?

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Python

I want to make a simple messaging application where I can send messages from my computer at home to my computer at my parent's place. I have created simple chat applications for LAN before but I have no idea where to start with WAN communication. TCP Tunneling? Port Forwarding is locked on our router, we cannot enable it. How does online games do it? I have never had to configure port forwarding to play DOTA with my friends through WAN.

I looked into the package "sshtunnel", but I did not understand how to communicate between two computers in pure python, seems like you need to configure SSH tunnels through separate software. I have tried searching APIs online but found none. Thank you in advance!

What I have tried:

The package "sshtunnel", but I did not understand it.