Btsync Over The Internet...through Firewalls Etc. in Sync General Discussion Posted June 29, 2014 · Report reply Hello:If I want to sync two servers, connected via the Internet, could someone please confirm the correct settings for 'listening port' and the NAT/uPnP setting? Whilst there is a 'listening port' setting in the GUI, there does not seem to be a 'sending port'.I am not sure about the effect of the NAT tickbox. I would like to sync two servers over the Internet, lets say using TCP Port 6666. That way I can set up firewalls and routers to direct this tcp port to the desired servers at each end of the link. Do I set both servers to 'listen' on port 6666? and turn off NAT?? Do they also 'send' on port 6666 if I do this?? Any information welcome.Thank you.