windows-wsl2-docker-ports.md

Port Usage for Windows/WSL2/Docker

Problem

Overnight (2022-09-15) a personal windows machine I have running a few docker services rebooted and docker containers failed to bind to ports:

Attaching to gitlab-gitlab-1
Error response from daemon: Ports are not available: exposing port TCP 0.0.0.0:51443 -> 0.0.0.0:0: listen tcp 0.0.0.0:51443: bind: An attempt was made to access a socket in a way forbidden by its access permissions.

Cause

A little research showed someone from a few years ago having the same issue and it was from Microsoft updating their range of dynamic/excluded ports. This is to comply further with the Service Name and Transport Protocol Port Number Registry.

Using the command: netsh interface ipv4 show excludedportrange protocol=tcp

I can see the ports currently used to expose the services are overlapping with the excluded port range:

Start Port    End Port
----------    --------
      5357        5357
     50000       50059     *
     50593       50692
     50693       50792
     50793       50892
     50893       50992
     51064       51163
     51164       51263
     51264       51363
     51364       51463
     51464       51563
     51564       51663
     51664       51763
     51764       51863
     51864       51963
     51964       52063
     52064       52163
     52164       52263

* - Administered port exclusions.

Solution

Although it could be possible to adjust the excluded port ranges, the easiest solution is to change the port mappings.

For my particular setup this is a minor hassle since I have two firewall layers with a DMZ and using Traefik as a load balancer. Still, the resolution isn't hard, just annoying.