Authoritative way to get the internal IP of a service

Hi. Render provides $RENDER_INTERNAL_HOSTNAME and $RENDER_INTERNAL_IP but neither are on the default environment variables list. I’d like to know the ip of each host so that I can occasionally forward requests to a specific host.

What’s the best way to do this? Thanks!

I believe this is a documentation omission, those variables are set by the execution environment and should always be there. Have you found a case where they aren’t?