Heimdall in a Docker in a LXD container

I apologize in advance if this question is outside the purview of this forum

Anyway, I am attempting to set up a docker instance of Heimdall in a 18.04 LXD container. Heimdall Installation

I followed the instructions and it seemed to have gone well but I cannot reach Heimdall from a browser. I suspect this may be a port issue? Irrespective of whether this is the case, I would love to know how the proxy device in LXD works.

For instance, what does

lxc config device add Container1 myport80 proxy listen=tcp: connect=tcp:localhost:80

actually do (I know what Container1 and myport80 are) but what is this REALLY doing? ELI5?

Sorry if this is really rudimentary but I am really enjoying learning LXD.

about the proxy I can’t do better than direct you to the documentation since I don’t use the LXD proxy myself. I have tested your app with straight redirections (one inside the container, one in the host) and I can connect to my host on port 8443 and use the app. That’s a way to do the job even if it does not use the LXD proxy.
If anyone knowing the proxy cares to answer, the app is a web application (PHP under nginx) and it answers to ports 8080 and 8443 on the docker0 network interface inside the container.
From what I see in your post, I’d dare to say that the connect should be to 8080, not 80.

Well irrespective of you own amount of knowledge, your response got my mind going in the right direction and I think I now understand. Heimdall is working within the LAN and I will check via WAN later.

Thank you!