hello giosal
I also have a Swisscom Internet connection. Swisscom tells me to stay on IPv4, if I run any web services and not to use IPv6.
I get only one public IP. In this case it’s a public IPv4. I can see, there is an IPv6 address showing on my Centro Business 2 from Swisscom, but this address is useless.
port forwarding is only relevant for IPv4. On IPv6 each device has it’s own public IP so there is no need to forward anything. what you do on IPv6, is punch holes into the router-firewall by allowing access to a specific local source from the internet. This can be done for everything or just specific tasks. By default all incoming requests from the internet are blocked.
On IPv4 you only have one public IP. In order to run a web service, your server needs to have this address assigned to it, or you use NAT by forwarding ports. So let’s say you run your own website (http uses port 80), any request from the internet to www.yourpublic.ip is sent to your router as yourpublic.ip:80 then your router translates this request into localip.webserver:80 and will forward the request to the server. The router will also translate the response from the server before it gets send out to the internet. Only the public IP is visible.
