How to check if the ISP uses Carrier-grade NAT (CGN)
It has been almost mandatory that mobile telephone operators now use CGN for their internet connections to save IPv4 addresses. it has also been more and more common among fiber and DSL ISPs. CGN is no problem for most common subscribers as they only need to browse the web, sending emails etc. eg. only need outgoing traffic. But CGN makes communication in the other direction, from outside Internet and in, impossible. This means that a Remoterig Radio-RRC cannot be used with an ISP using CGN. For the control-RRC it’s OK. In most cases it’s possible to get a real public IP-addresses from the ISP for free just by calling them, but in some cases you have to pay extra for it.
More info about CGN
https://en.wikipedia.org/wiki/Carrier-grade_NAT
To check if your ISP is using CGN you need to connect a PC to the router at Radio QTH.
When you are up and in connection with the Internet and can browse the web go to
http://www.whatsmyip.org/
or any similar page which will show from which public IP address your request is coming. This address is always a public IP-address, nothing else works.
After that, login to your router and look at the status page. The router will report which WAN IP-address it has got from the ISP.
If it shows the same IP-address as whatsmyip everything is OK and it will work with Remoterig.
If the router shows another WAN IP-address it’s NOT OK, the ISP is using CGN.
If CGN is in use the router often shows a WAN IP address like 100.xxx.xxx.xxx or 10.xxx.xxx.xxx.or 192.xxx.xxx.xxx.