Access Windows host from WSL 2

wsl-host.ps1

# Access host ports from WSL 2.
# https://gist.github.com/vilic/0edcb3bec10339a3b633bc9305faa8b5

# Make sure WSL gets initialized.
bash.exe -c exit

# Record host name for /etc/hosts that points to host IP.
$HOST_NAME = "host.wsl";

# Ports listened on host localhost to forward, you don't need to add the port if it listens all addresses.
$HOST_LOCALHOST_PORTS = @(52698);

$FIREWALL_RULE_NAME = "wsl";
$FIREWALL_RULE_DISPLAY_NAME = "WSL";

Write-Output "Detecting WSL IP address...";

$hostIP = wsl -- bash -c "tail -1 /etc/resolv.conf | cut -d' ' -f2";
$wslIP = (wsl -- ip address show eth0 | Select-String -Pattern "inet ([\d.]+)").Matches.Groups[1].Value;

Write-Output "Host IP address: $hostIP";
Write-Output "WSL IP address: $wslIP";

Write-Output "Updating hosts record $HOST_NAME ($hostIP) for WSL...";

wsl --user root -- echo "$hostIP`t$HOST_NAME" ">>" /etc/hosts;

Write-Output "Updating firewall rule...";

Remove-NetFireWallRule -Name $FIREWALL_RULE_NAME -ErrorAction Ignore;

New-NetFireWallRule `
  -Name $FIREWALL_RULE_NAME `
  -DisplayName $FIREWALL_RULE_DISPLAY_NAME `
  -Direction Inbound `
  -LocalAddress @($hostIP)`
  -Action Allow;

Write-Output "Setting up localhost port proxies...";

foreach ($port in $HOST_LOCALHOST_PORTS) {
  $previousRecordGroups = (netsh interface portproxy show v4tov4 | Select-String "(\S+)\s+$port\s+127\.0\.0\.1\s+$port").Matches.Groups;

  if ($null -ne $previousRecordGroups) {
    $previousHostIP = $previousRecordGroups[1].Value;
    netsh interface portproxy delete v4tov4 listenport=$port listenaddress=$previousHostIP | Out-Null;
  }

  netsh interface portproxy add v4tov4 listenport=$port listenaddress=$hostIP connectport=$port connectaddress=127.0.0.1 | Out-Null;
}

Write-Output "Done.";

And now it prevents Docker Desktop from starting at all! The smoke test of Docker Daemon availability is curl http://localhost/engine/state
returns curl: (7) Failed to connect to localhost port 80: Connection refused. The docker Host definition is placed into Windows hosts file in the WINDOWS ... Drivers\etc\hosts and it is correct - it points to the Host Machine IP on which all Docker and its Orchestration engines related ports are exposed and available for the outside world via host IP:port. The Host name in the Windows hosts file is called hot.docker.internal with IP achieved from external DHCP. All networks inside Windows are bridged to the host network by default or by explicit declaration about reuse of the Host communication layer.
Processes running inside WSL VM can communicate with each other via Host ports if Windows firewall allows access to the Hosts ports in both directions! It shall be defined by Windows defender rule which shall allow:
Client inside WSL VM TCP -> host.docker.internal : 80, 343, 256, 257, .., everything exposed by Docker . -> Docker engine inside WSL VM IP.
If requests from outside are served by a Proxy 1st such a proxy can run as Windows process or Docker container, i.e. inside WSL VM Proxy shall be able to reach every process, Windows service, WSL subprocess with own IP and be available from Linux CLI client.
Shortly - bidirectional communication between WSL and Host shall be allowed for certain ports.

C:\WINDOWS\system32>

Updated the implementation and now it append the hosts file inside WSL.

I reconfigure my network in the top-down manner i.e. had configured IPV4 DNS list in my router, then configured Windows, shut down and re-start WSL, and in some magic way Resolv.conf got the top DNS in my DNS list in the Router's Resolv.conf. In other words, there are smart home routers, like Technicolor that can manage the Home network as an SDN network.
From the other hand, I afraid that it blocks any access to devices or WSL VMs via ports reserved for Internet using its built-in firewall

Thank you, this helped me a great deal!