Hi.
I am using your tvheadend image on my synology in host mode and everything is working fine.
But when I enable my synology firewall Kodi cannot connect to tvheadend.
I opened port 9981 and 9982 in the firewall, but that is not enough. I cannot start streaming tv.
Are there any other ports to open?
I don’t use tvheaderd, but based on the experience I’ve had with my other containers, my guess would be the problem is that you don’t have a LAN domain setup, so that when one of your local devices tries to hit e.g. tvheader.domain.com, it’s going out to the internet to find it, so for it to work you’d have to set up DNS records pointing your domain to your WAN IP, open whatever port swag is running on and forward that to the IP of whatever swag runs on, in other words opening it externally (a Cloudflare Tunnel or similar would probably work too).
This was driving me nuts as I didn’t want my local area network reaching out over the internet just to get to other LAN devices. So in my router (I’m using DD-WRT) I just set up my domain as a LAN domain, so if I’m at home, it just goes straight to it, and if I’m outside the house (e.g. on a laptop) it still works fine as I do have mine externally accessible.
I think I was a bit inaccurate 
I dont want external access to tvheadend. I am only using it in my local lan via kodi.
I just would like to know which ports I have to open that it works.
Nobody an idea?
I bet the tvheadend documentation would say which ports are used… did you check there?
As a note, we support the container, not the application