Wireguard

Introduction

Using a VPN allows remote access to a server’s local resources without exposing them to the internet. It’s a clean and secure way to access services like SSH without exposing the port publicly. With a VPN, you can securely connect to your network from anywhere and make devices on different networks communicate.

Here we will use Wireguard, a secure and high-performance VPN server, using containers:

• wg-easy as the server, providing a very simple web UI to manage connections and download config files (including QR codes for phones)
• Wireguard as the client for Linux systems

Clients are also available for Windows, macOS, iOS, and Android.

The concept:

• On the internet, anyone can reach any internet box and thus any exposed server.
• Your server is on your local network. It is accessible only locally unless services are explicitly exposed (as we did with Dockge). To access non-exposed resources, you must be on the same local network.
• We want to securely access these unexposed services (like SSH) from anywhere.
• We also want to connect services between servers, like linking two Dockge instances securely.

To achieve this, we’ll create a Virtual Private Network (VPN), i.e., a secure tunnel that only connected machines can use. They’ll appear to be on the same private network.

Additionally, you can add your phone, laptop, or other devices to the VPN and securely access your server resources wherever you are.

In this diagram, machine 1 is part of two networks:

• Its local network (devices behind the same router, e.g. 192.168.x.x – machines 1 and 2)
• The VPN network (VPN devices with a second IP, e.g. 10.8.x.x – machines 1 and 4)

You can allow VPN clients to share access to their local networks, but we won’t do that here for security and subnet conflict reasons (e.g., if two remote machines use the same local IP like 192.168.1.1).

So only VPN-connected devices can communicate with each other on the VPN, not with other local devices outside the VPN.

Server Side

Folder structure:

root
└── docker
    └── wg-easy
        ├── config
        │   └── etc_wireguard
        ├── compose.yaml
        └── .env

The container runs in HOST mode, meaning it uses the host’s network stack directly.

Open Dockge, click compose, and name the stack wg_easy.

Paste the following configuration:

---
volumes:
  etc_wireguard:
services:
  wg-easy:
    network_mode: host
    env_file:
      - .env
    environment:
      - LANG=en
      - WG_HOST=${HOST}
      - PASSWORD_HASH=${PW}
      - WG_DEFAULT_ADDRESS=${ADDRESS}
      - WG_HIDE_KEYS=never
      - WG_ALLOWED_IPS=${IPS}
      - WG_DEFAULT_DNS=
      - UI_TRAFFIC_STATS=true
      - UI_CHART_TYPE=1
    image: ghcr.io/wg-easy/wg-easy:14
    container_name: wg-easy
    volumes:
      - /docker/wg_easy/config/etc_wireguard:/etc/wireguard
    restart: unless-stopped
    cap_add:
      - NET_ADMIN
      - SYS_MODULE

services
  wg-easy:
    #...
    labels:
      - com.centurylinklabs.watchtower.enable=true

In .env:

HOST=
PW=
ADDRESS=
IPS=

Deploy the stack.

Enable Forwarding on Host

To allow communication between VPN clients, enable:

sudo sysctl net.ipv4.ip_forward=1
sudo sysctl net.ipv4.conf.all.src_valid_mark=1

Retrieve Configuration Files

To configure clients, download the config files from the server:

• Visit http://your-server-ip:51821
• Create a client
• Download the config file
• Rename it to wg0.conf

On the Client Server

Folder structure:

root
└── docker
    └── wireguard
        └── config
        │   └── wg_confs
        └── compose.yaml

Create the folder /docker/wireguard/config/wg_confs:

sudo mkdir -p /docker/wireguard/config/wg_confs

Copy the wg0.conf file downloaded earlier:

sudo cp ~/wg0.conf /docker/wireguard/config/wg_confs

Create compose.yaml in /docker/wireguard:

sudo vi /docker/wireguard/compose.yaml

Press i to enter insert mode and paste:

services:
  wireguard:
    image: lscr.io/linuxserver/wireguard:latest
    container_name: wireguard
    network_mode: host
    cap_add:
      - NET_ADMIN
      - SYS_MODULE #optional
    environment:
      - TZ=Europe/Paris
    volumes:
      - /docker/wireguard/config:/config
      - /lib/modules:/lib/modules #optional
    restart: unless-stopped

Press Esc then type :x to save and exit.

Start the container:

cd /docker/wireguard
sudo docker compose up -d

Other Devices

• Phone: Install Wireguard and scan the QR code from the web UI (http://your-server-ip:51821)
• PC: Install the Wireguard client and import the config file

And this is the result: