Idk how zimaos works, but the way to attach containers like this is with network_mode: “service:othercontainer” which might need them to be in the same compose file (the docs aren’t clear).

network_mode: “container:gluetun”

Is how you can do it with separate compose files. And yes you’d need to map the ports in the gluetun compose file for any container you route through gluetun.