Port mapping does not work anymore

Windows Server 2016
1

Expected behavior

When starting a container with docker run and the flag -p 104:104, the port 104 of the host should be mapped to the port 104 inside the container.

Actual behavior

The port is not mapped. It is only reachable via the ip of the docker container instance, retrieved via docker-inspect.

Information

Host OS is Windows Server 2016 14393

This has definitely worked last year, not sure which version that was.

Steps to reproduce the behavior

Can be reproduced even with the sample iis container:

  1. docker run -p 8080:80 microsoft/iis
  2. Access localhost:8080 -> not reachable
2

Ok, it does work if I directly use the IP of the system, and not localhost or 127.0.0.1. Although I’m sure this has worked in the past.