Remote connection

Good morning, i have a problem with the remote connection. I use the program connected to an S7-300 PLC on the wi-fi network and it’s ok. I configured the “remoteHost” with the ip address (fixed) of my router but with the 3G connection it does not work. What port number should be opened on the router? Modifications to the CP PLC side are required? Thank you very much and congratulations for the app.