> ## Documentation Index
> Fetch the complete documentation index at: https://docs.allthingslinux.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Coturn

# Coturn TURN/STUN Server

**Service:** TURN/STUN Relay
**Container Name:** `coturn`
**Image:** `coturn/coturn`
**Network Mode:** `host` (Critical for performance and NAT traversal)

***

## Configuration

Located at: `./services/coturn/turnserver.conf`

### Key Settings

* **`listening-port`**: 3478 (UDP/TCP)
* **`tls-listening-port`**: 5349 (TLS/DTLS)
* **`network_mode: host`**: The container shares the host's networking stack.
* **`fingerprint`**: Enabled.
* **`denied-peer-ip`**: Localhost/Private ranges blocked to prevent internal relay attacks.

### Environment Variables

* **`EXTERNAL_IP`**: **REQUIRED**. You must set this in your `.env` file.
  * This is passed to the container via the command line: `--external-ip ${EXTERNAL_IP}`.
  * Example: `EXTERNAL_IP=<YOUR_EXTERNAL_IP>`

### Firewall Requirements

Host firewall (UFW/Security Group) must allow:

* `3478`, `3479` (TCP/UDP) - Standard & Alt Listener
* `5349`, `5350` (TCP/UDP) - TLS & Alt TLS Listener
* `9641` (TCP) - Prometheus Metrics
* `49152-65535` (UDP)

***

## Testing

1. **Docs**: [Metered.ca Coturn Guide](https://www.metered.ca/blog/coturn/) (Reference)
2. **Tool**: [Trickle ICE](https://webrtc.github.io/samples/src/content/peerconnection/trickle-ice/)
   * STUN: `stun:turn.atl.network:3478`
   * TURN: `turn:turn.atl.network:3478` (User: `admin`, Pass: `changeme`)