Ground2Cloud does not rely on any incoming (ingress) ports, but outgoing (egress) ports 3014, 3016, 8100, 22, 80, and 443 need to be allowed out to the G2C server.
You can see the default connection setup under the config tab of the UI:
In addition, to connect your local service to the G2C client, configure the
[client.local] to match the local settings.
Open up the G2C GUI, go to "Manage", and change "Service Host" and "Service Port" to the hostname (usually localhost) and port number that the Footprint service is running
For example, if I'm running a PostgreSQL server locally, my configuration would look like this: