I recently spent hours trying to through a Twingate connector running on my macOS machine. The setup seemed straightforward: deploy the Twingate connector using Docker, configure an SSH resource, and connect remotely. However, I kept hitting a frustrating "end of file" error whenever I tried to SSH to the same machine running the connector.
What I discovered was a fundamental architectural limitation that Twingate doesn't clearly document: Docker containers on macOS cannot reliably access services running on the host machine. This affects anyone trying to use Twingate to access services on the same macOS/Windows device running the connector.
Note : This is exactly why Windows and macOS or not natively supported by Twingate and you need containerization (in this example Docker)
The Problem: Docker Containerization on macOS
My goal was simple:
- Run a Twingate connector on my macOS machine using Docker
- Create an SSH resource pointing to the same macOS machine
- Connect via SSH from a remote location through Twingate
What Actually Happened
The Twingate connector deployed successfully and showed as "Online" in the admin console. When I attempted to SSH through Twingate, the connection would establish initially but then immediately fail with an "end of file" error. This indicated that the TCP connection was being made but then abruptly terminated.
Why did this fail?
The issue wasn't with my SSH configuration, firewall settings, or Twingate resource setup. The problem was Docker's network isolation on macOS. When you run a Docker container on macOS, it cannot reach services running on the host machine due to the way Docker Desktop works on non-Linux systems.
Here's what was happening:
- My SSH client connected to Twingate successfully
- Twingate routed the connection to the connector
- The connector (running in Docker) tried to reach SSH on the host
- Docker's network isolation blocked the connection
- The connection was established but immediately closed, causing "end of file"
Why Docker Networking Fails on macOS
The Architecture Problem
On macOS, Docker Desktop runs containers inside a Linux virtual machine, creating multiple layers of network isolation:
macOS Host (SSH service on port 22)
↕ (Barrier 1: VM boundary)
Linux VM (Docker Desktop)
↕ (Barrier 2: Container network)
Docker Container (Twingate Connector)
The Twingate connector, running inside the Docker container, simply cannot reach services on the macOS host due to this double isolation.
The macOS vs Linux Misconception
There seems to be a common misconception that macOS is essentially Linux - unfortunately, while it does behave a little like Linux it’s not - Twingate on both solutions does use Docker.
This architectural difference has a huge impact on networking:
On Linux:
Linux Host
└── Docker Engine (native)
└── Container (shares kernel, easy host access)
On macOS:
macOS Host
└── Linux VM
└── Docker Engine
└── Container (isolated from macOS host)
What Twingate Should Document - in my view....
This experience revealed a significant gap in Twingate's documentation. They should clearly state:
⚠️ macOS Docker Limitation: Docker Desktop on macOS cannot provide reliable connector access to services running on the same macOS host due to Docker's VM architecture. For same-host access, deploy the connector on a separate device.
Conclusion
This issue highlights how containerization can create unexpected limitations when moving between operating systems. What works perfectly in a Linux production environment may fail in development environments on macOS or Windows due to fundamental architectural differences.
Understanding these differences is crucial for anyone deploying containerized applications across different platforms. The assumption that "containers work the same everywhere" is simply not true when it comes to host networking and resource access.