Access LAN Devices from Docker Containers on macOS (e.g., MariaDB) Published at 2025-06-04

Couple of weeks ago, I bought Raspberry Pi 5 and use it as my home server (currently only for entertainment and database). And this raspi5 live in my internal home network with IP 192.168.100.100. I can access it easily through my Linux, Windows, and Mac machine.

After updating Docker Desktop, I found that my docker containers can no longer access devices on my local network (e.g., 192.168.100.100). After doing some research, this is because Docker Desktop runs containers inside a VM, which is isolated from physical LAN — especially on macOS (I’m using Mac Mini M4 btw).

In this post, I’ll show how to work around this limitation using a simple but powerful tool: socat.

The Problem

On macOS, Docker runs in a VM that uses NAT networking. This means:

  • Containers can access the internet (e.g., ping 8.8.8.8)
  • But they cannot access local devices (e.g., 192.168.100.100)
  • Bridged networking is not supported natively

The Solution: Create a Proxy in my Mac

I can make my Mac Mini act as a bridge between the container and LAN using socat, a lightweight TCP proxy.

Example Use Case

Access a MariaDB server running on 192.168.100.100:3306 from inside a Docker container.

Step-by-Step Guide

1. Install socat on macOS

$ brew install socat

2. Start the TCP Proxy

$ socat TCP-LISTEN:33060,fork TCP:192.168.100.100:3306

This tells socat to listen on my Mac port 33060 and forward the traffic to MariaDB server on my LAN.

3. Connect from Docker Container

You can try to connect from container like this

$ mysql -h host.docker.internal -P 33060 -u root -p

Thanks for stopping by. This post is honestly for my personal note, hope this helps. See ya