Docker VPN and Proxy Containers

Setting up a VPN in a Docker container is very useful. You can utilise it in various ways without tunneling your entire network traffic through the VPN.

I’m currently using ProtonVPN and Protonwire as the container. It wouldn’t be too difficult to roll your own container if the VPN has CLI software (or OpenVPN or WireGuard config).

My Docker compose starts with:

services:
  protonvpn:
    container_name: protonvpn
    image: ghcr.io/tprasadtp/protonwire:latest
    networks:
      # Docker network to provide VPN access
      - vpn
    ports:
      # Expose port of the proxy container
      - "1080:1080/tcp"

The vpn network is an external overlay network referenced in the config:

networks:
  vpn:
    external: true

And created like so:

docker network create -d overlay --attachable vpn

A bridge network can work if the containers are on a single machine. An overlay network allows docker containers on other machines to connect (via docker swarm mode).

Containers on the same bridge or overlay network can add:

    network_mode: "container:protonvpn"

This forces the container to use the VPN for internet access.

Using the VPN is not limited to other containers.

In the same docker-compose.yml config I added a proxy service:

  socks5:
    image: serjs/go-socks5-proxy
    container_name: socks5
    environment:
      - PROXY_PORT=1080
    depends_on:
      - protonvpn
    network_mode: "service:protonvpn"

Because network_mode is set to the VPN container the proxy port is not exposed here but on the vpn container. The proxy container allows VPN access from outside Docker by apps on the local system or network.

Proxy usage examples:

Command Line

Many command line apps like curl allow you to specify a proxy option:

curl --proxy socks5://127.0.0.1:1080 https://icanhazip.com/

They may also respect the https_proxy environment variable:

https_proxy=socks5://127.0.0.1:1080 curl https://icanhazip.com/

JavaScript / Deno

Deno has an unstable API that allows you to proxy fetch requests:

const client = Deno.createHttpClient({
  proxy: {
    url: `socks5://127.0.0.1:1080`
  }
});
const response = await fetch(`https://icanhazip.com/`, {client});
console.log(await response.text());

Firefox Tabs

Firefox Multi-Account Containers is an official plugin by Mozilla. The plugin allows you to create sessions where local storage like cookies are separated. You can also configured these sessions to use a HTTP proxy.

This set up means that browsing the web using a VPN is as simple as opening a new tab. You could have multiple tabs open using multiple VPNs whilst others use non.

Why?

For one, there’s the obvious questionable content like downloading cars and seeding linux ISOs. It’s also useful to test/hammer APIs when you’re too lazy to read the documentation. Or you have a crazy idea like transfering files via web push notifications.

If you value your privacy and data at all you’re probably aware of how insidious tracking and fingerprinting is across the web. I use a VPN to watch YouTube, for example.

I’m not going to promote one particular VPN but just warn that free/cheap should not be an attractive proposition for VPN services.

DNS

Bear in mind that DNS queries may not be proxied using this set up. I have a separate and rather complicated set up to handle DNS (I should blog about that some day…). At the very least configure your router with an upstream DNS service like Quad9.

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Have suggestions to improve this set up? @dbushell!