ROOT_URL can be problematic

[macrozone]

as your question is still missunderstood, here a solution that might help, at least for dynamic imports:

[SOLVED] Dynamic import fails when not serving from ROOT_URL

Turns out the dynamic import package has a not-so-well-documented setting that uses the window.location value as a basis for fetching data. Just put it in the public section of your meteor settings { "public": { "packages": { "dynamic-import": { "useLocationOrigin": true } } } } Along with a strict CSP header, this does not compromise security.

so setting

{
  "public": {
    "packages": {
      "dynamic-import": {
        "useLocationOrigin": true
      }
    }
  }
}

this fixes lazy load on different hosts (e.g. hostname and ip adress).

you still can’t use relativ paths, but i think that would not be a solution to your problem.

Be aware that ROOT_URL might also be used in stuff like emails (for password reset links), but that should be easier to work around.

Another solution is to configure the DNS in your private network to resolve the public hostname to the internal ip adress