Sync Vault Doc

Start a TURN Server

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What is a TURN Server?

A TURN server acts as a “relay station” or “translator” that enables direct communication between devices behind network “firewalls” or “NAT”. When two devices cannot establish a direct “handshake” connection, all their data is relayed through this intermediate server. When using Real-Time Sync, if devices fail to discover each other directly, a TURN server is required for data relay.

Do I Need a TURN Server?

graph TD 
A(All devices are on the same LAN, e.g., home or office network) 
A1(External network devices need to join the connection) 
B1(Required) 
B2(Not required) 

A1-->B1 
A-->B2

You can quickly set up a TURN server by Setting Up a TURN Server with Coturn. For NAS users, refer to Setting Up on NAS.

Setting Up a Relay Service with Coturn

Coturn is a powerful open-source STUN/TURN server.

1. Preparation

Before starting, you need:

  • A server with a public IP address (e.g., a cloud server).
  • A recent Linux distribution (e.g., Ubuntu 20.04/22.04 LTS) installed on the server.

Network Port Requirements:

  • 3478 TCP/UDP: Standard port for STUN/TURN services.
  • 5349 TCP/UDP: TLS-encrypted port for TURN services.
  • 49152-65535 UDP: Port range for relaying media streams (adjustable if needed).

Ensure your server firewall (e.g., ufw) or cloud provider’s security group rules allow the above ports. For example, on Ubuntu with UFW, run the following commands:

bash

sudo ufw allow 3478/udp
sudo ufw allow 3478/tcp
sudo ufw allow 5349/udp
sudo ufw allow 5349/tcp
sudo ufw allow 49152:65535/udp # Open relay port range
sudo ufw reload

2. Installation

On Ubuntu/Debian, install using the apt package manager:

bash

sudo apt update
sudo apt install coturn

3. Configuring Coturn

Coturn’s main configuration file is typically /etc/turnserver.conf or /usr/local/etc/turnserver.conf. It is recommended to back up the original file first.

Configuration ItemExample ValueDescription
listening-ip0.0.0.0IP address the server listens on; 0.0.0.0 means all available network interfaces.
listening-port3478UDP/TCP port for STUN/TURN services.
tls-listening-port5349TLS-encrypted port for TURN services.
external-ipYour Public IPCritical! Your server’s public IP. If the server has multiple IPs or is behind NAT, use the format Public IP/Private IP.
relay-ipServer Private IPIP used for relaying traffic (usually the server’s private IP).
min-port

max-port		49152

65535		UDP port range for TURN relay. Must match firewall settings.
userusername:passwordUsername and password for long-term credential authentication (plaintext, for testing).
realmyourdomain.comRealm identifier (usually your domain or server’s public IP), used for client connections.
lt-cred-mech(No value)Enables long-term credential authentication.
fingerprint(No value)Adds a fingerprint attribute to STUN/TURN messages for enhanced security.
cert

pkey		/etc/ssl/turn_cert.pem

/etc/ssl/turn_key.pem		Paths to TLS certificate and private key (supports Let’s Encrypt or self-signed certificates).
no-tlsv1

no-tlsv1_1		(No value)Disables insecure TLS protocol versions.
log-file/var/log/turn.logPath to log file (facilitates troubleshooting).
verbose(No value)Enables detailed log output.

A basic configuration file example (/etc/turnserver.conf):

ini

# Network Listening Configuration
listening-ip=0.0.0.0
listening-port=3478
tls-listening-port=5349
external-ip=Your Public IP Address # e.g., 123.456.789.123
relay-ip=Your Private IP Address   # e.g., 172.31.0.10
 
# Relay Port Range
min-port=49152
max-port=65535
 
# Domain and Authentication
realm=Your Domain or Server Public IP # e.g., turn.yourdomain.com
lt-cred-mech
user=Your Username:Your Password # Long-term credential (plaintext, for testing)
# It is recommended to use turnadmin to create dynamic users:cite[2]
# Or use use-auth-secret and static-auth-secret:cite[2]
 
# Security and TLS
fingerprint
cert=/etc/ssl/turn_cert.pem    # Path to TLS certificate
pkey=/etc/ssl/turn_key.pem     # Path to TLS private key
no-tlsv1
no-tlsv1_1
cipher-list="DEFAULT"          # List of encryption suites:cite[8]
 
# Logs
log-file=/var/log/turn.log
verbose # Disable in production to avoid excessive log size
 
# Others
stale-nonce
no-multicast-peers
no-cli:cite[8]

4. Starting and Testing

Start the Coturn service:If installed via apt, Coturn is set up as a systemd service. Start and enable it with:

sh

sudo systemctl start coturn    # Start the service
sudo systemctl enable coturn   # Set to start on boot:cite[10]

Check service status and logs:Verify if Coturn is running properly with these commands:

sh

sudo systemctl status coturn   # Check service status
sudo tail -f /var/log/turn.log # View real-time logs (if log-file is configured):cite[10]
netstat -tuln | grep -E ':(3478|5349)' # Check if ports are listening

Test the TURN server:Online Tool Test:Google provides a convenient WebRTC ICE Candidate Collection Test Page:

  1. Open a browser and visit: https://webrtc.github.io/samples/src/content/peerconnection/trickle-ice/

  2. In the IceServers box, delete the default content and add your TURN server information in the following format:

    json

    {
  "urls": "turn:Your Public IP:3478",
  "username": "Your Username",
  "credential": "Your Password"
}

5. Sync Vault Configuration

Open Sync Settings > Self-Hosted Configuration, and enter the TURN server details in the input box:

sh

// Format: turn:host:port?username=xxx&password=xxx

Click the cloud icon to automatically establish a peer-to-peer connection.

Setting Up a Relay Service on NAS

A NAS is an excellent platform for hosting a TURN server, especially for home labs or personal projects. Its 24/7 operation and low power consumption make it ideal for running such persistent services.

Setting Up a Relay Service with Coturn covers Coturn-based TURN server setup. For NAS deployment, there are three main methods depending on your NAS model and system:

MethodApplicable ScenariosAdvantagesDisadvantages
DockerMost modern NAS (Synology, QNAP, ASUSTOR, etc.)Highly recommended! Easy deployment, good isolation, no system pollution, easy management and migration.Requires basic Docker knowledge
Native InstallLinux-based NAS supporting apt or pkg (e.g., TrueNAS Scale)Slightly better performance, direct controlMay depend on system version, risk of conflicts with other system components
Virtual MachineAll NAS supporting virtualizationFull isolation, maximum flexibilityHigher resource consumption, more complex setup

🎈 Docker-based setup is recommendedThis is the simplest and most secure method, suitable for most NAS brands like Synology (DSM), QNAP, and ASUS.

1. Preparation

  • Enable SSH access: Activate SSH in your NAS control panel to execute commands via the terminal.
  • Install Docker: Search for and install the Docker app (e.g., Synology’s “Container Manager”) in your NAS’s Package Center or App Center.
  • Plan file paths: Create a folder on your NAS to store Coturn’s configuration files and logs (e.g., /docker/coturn).

2. Create a Configuration File

Connect to your NAS via SSH or use the NAS’s built-in text editor to create a file named turnserver.conf in the folder you just created (e.g., /docker/coturn):

sh

# Navigate to the directory and create the file
cd /volume1/docker/coturn
vim turnserver.conf

Paste the following configuration content into the file, and modify the parts marked in comments according to your setup:

ini

# Basic Configuration
listening-port=3478
tls-listening-port=5349
min-port=10000
max-port=20000
 
# ！！！Critical Step: Enter your public IP or DDNS domain ！！！
external-ip=Your Public IP or DDNS Domain
 
# Authentication Configuration (use long-term credentials; modify the password)
lt-cred-mech
user=Your Username:Your Password
realm=Your Public IP or DDNS Domain
 
# Network and Security Configuration
fingerprint
verbose
no-multicast-peers
 
# If your NAS has multiple IPs, specify relay-ip (optional)
# relay-ip=Your NAS Private IP
 
# Log Output (optional)
log-file=/var/log/turn.log
simple-log

3. Start the Docker Container

Create the container using your NAS’s Docker GUI (e.g., Container Manager) or via SSH command line.

GUI Operation Steps:

  1. Open Container Manager.
  2. Go to “Registry”, search for coturn, and download the official image coturn/coturn.
  3. After download, find the image in “Images” and click “Launch”.
  4. In “Advanced Settings”:
    • Network: Select “Use the same network as Docker Host” (host network mode) to avoid complex port mapping.
    • Volumes: Add a folder mapping—mount /docker/coturn/turnserver.conf (on your NAS) to /etc/coturn/turnserver.conf (inside the container).
    • Environment Variables (optional): Add TURNSERVER_ENABLED=1.
  5. Complete the setup and run the container.

SSH Command Line Example (More Efficient):

bash

docker run -d \
  --name=coturn \
  --network=host \
  --restart=always \
  -v /volume1/docker/coturn/turnserver.conf:/etc/coturn/turnserver.conf \
  coturn/coturn
  • -d: Run in the background
  • --name=coturn: Name the container “coturn”
  • --network=host: Use host network mode to simplify network configuration
  • --restart=always: Auto-restart the container if the NAS reboots
  • -v ...: Mount the local configuration file to the container

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