Hello,
I found this other post that is related Container to Container communication by host rule
And also that SO ssl - Docker Traefik can't resolve DNS (Fails reaching server and obtaining certificates) - Stack Overflow
And all possible solutions seem to be listed in this repo (I'm unable to find the original post where I saw this link) GitHub - flexguse/traefik-inter-container-routing: Demo setup for showing how Docker container communication with traefik routing can be used.
Though I didn't tested any of those solutions, I think any of those won't really help (unless I'm not understanding well)..
Let me explain..
For me having a solution that needs me, after each app/service I launch, to go back to the Traefik config and add some options (the container alias names method) remove the interest of having Traefik handling everything automatically.
The same goes for the Add host entry to container method, which needs me to launch the app/service and grab its IP and then go back to the config in order to add the IP.. Not very dynamic nor automatic IMHO..
The set DNS servermethod, I'm not sure it will work, since I don't have any problem to reach the internet (e.g. google.com or whatever domain) from the services..
So the problem I still have is that if I want one service to access another service with its FQDN (when both of my services are behinf traefik) it doesn't work.
I could have use the services name if all my services where within the same docker-compose file but they are not..