Hi,
Just adding some information here and hope it helps.
DS-Lite means:
- you have your own IPv6 address (so you are reachable via IPv6)
- you share an IPv4 address with many users (packets are transferred to you via NAT - that’s why you are not reachable via IPv4)
Disabling DS-Lite to me sounds like:
- you no longer get an IPv4 address
- you will only surf the Internet with your IPv6 address
- you won’t be able to connect to servers that have an IPv4 address only
The other option that allows you to connect to your server is Dual Stack = DS (no DS-Lite then):
- ask your ISP for a dedicated (your own) IPv4 address
- that usually costs a bit (5,- €/ month for me)
- FreeDNS will perfectly work without any efforts
While you have DS-Lite right now and therefore only your own IPv6 (no own IPv4), you can access your server as long as you only use your IPv6 address. And this means, that your DNS service should support IPv6 and you should only publish your IPv6 address.
One thing is very important when it comes to IPv6. It is different to IPv4 in terms of NAT and Port Forwarding and actually doesn’t work that way.
In order to make your server reachable via IPv6, you need to enable IPv6 in your home LAN and publish your server’s IPv6 address to the DNS service (FreeDNS in this case).
Additionally, you need to open the specific port on the router, to allow packets to pass the firewall to your server. In some routers, it is called IPv6 forwarding, while it is actually only a port opening.
Let me know if you need further explanation. I just wanted to mention, that DS-Lite doesn’t generally mean, that you can’t reach your server from the outside. It only means you can’t reach your server via IPv4.
Edit: oh and for Let’s Encrypt: it needs to reach your server (or with DNS challenge your DNS settings). That means, you first need to make your server available and then get a cert from Let’s Encrypt.