Thanks for your response. Unfortunately IPv6 is a bit more than I am prepared to throw on the current configuration (QNAP server hosting virtual machines and docker containers, oh my). I think I'll stick to dockerizing a DNS server, point LAN clients to it using DHCP, and there host my private domain, forwarding everything else (ie. split-zone DNS configuration, as external to my network the public DNS servers will respond with public addresses). It will probably take me less time to implement this than Swisscom to release new firmware 😐
After my Internet box plus got its firmware updated to 10.3.36 my setup no longer works - I’m running a small web server on LAN, and have port forwarding enabled on ports 80 and 443. I am still able to access the site from external networks, but when I’m home, connected to the LAN, the site no longer works. Before the update it was working fine, with the internet box routing the traffic correctly. Do I have any option besides running an internal DNS server on LAN and splitting my DNS domain between internal and external networks?