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How to expose a server on WSL2 to the LAN using SSH tunneling

· 2 min read
ひかり
ひかり
Main bloger

Step1. Install OpenSSH Server on WSL​

Install OpenSSH Server on WSL2. Also, start the sshd service.

# WSL2 side
sudo apt install openssh-server
sudo service sshd start

Step2. Register the public key on the Windows side​

If you have not registered the public key on Windows, run the following command.

# Windows side
ssh-keygent -t ed25519

Next, register the public key on WSL2.

# Windows side
$pubkey = $(cat $HOME\.ssh\id_ed25519.pub)
wsl -- echo $pubkey `| tee -a `$HOME/.ssh/authorized_keys

Step3. Tunnel with SSH​

Connect to WSL2 from Windows via SSH.

# Windows side
ssh (wsl -- hostname -I).trim() -g -L8081:localhost:8080

Explanation of the command:

  • (wsl -- hostname -I).trim() retrieves the IP address of WSL2.
  • -g forwards the port to the LAN (accessible from external devices with an address like 192.168.x.x).
  • -L is the local forward option. It forwards the server's port to a local port.
  • 8081 and localhost:8080 mean that accessing http://localhost:8081 will forward to localhost:8080. Here, localhost refers to localhost as seen from the server side.

Step4. Start the server​

Start the server that you want to expose on WSL2.

# WSL2 side
ruby -run -e httpd . # Directory listing will be exposed

Step5. Access the server​

You can access the service at http://localhost:8081 or http://<IP address displayed by ipcconfig>:8081.

A disadvantage of tunnel connections is that it is tedious to tunnel every time. Although unstable, you can do the same thing by using netsh interface portproxy ~.