# Testing Pomerium UDP Tunnels with Ethr

Since v0.29.0 Pomerium supports tunneling UDP traffic. This example demonstrates how to do this using [Ethr](https://github.com/microsoft/ethr), a network performance measurement tool.

You will need two machines: one running the Ethr client and the Pomerium CLI, and another running the Ethr server and Pomerium. Replace **`ethr.corp.example.com`** with your domain name.

## Server

1. Install Pomerium

2. [Install Ethr](https://github.com/microsoft/ethr?tab=readme-ov-file#installation)

3. Enable QUIC by setting [`codec_type`](https://www.pomerium.com/docs/reference/codec-type.md) to `http3`

   ```yaml
   codec_type: http3
   ```

   Pomerium also supports UDP tunneling with `http1` or `auto` (the default), but using `http3` significantly improves performance.

4. Add a UDP route on port 8888

   ```yaml
   - routes:
       from: udp+https://ethr.corp.example.com:8888
       to: udp://127.0.0.1:8888
       allow_any_authenticated_user: true
   ```

5. Run Pomerium

6. Run the Ethr server

   ```bash
   ethr -s
   ```

## Client

1. Install the Pomerium CLI

2. [Install Ethr](https://github.com/microsoft/ethr?tab=readme-ov-file#installation)

3. Start a UDP tunnel

   ```bash
   pomerium-cli udp ethr.corp.example.com:8888 --listen :8888
   ```

   If you don't have a valid certificate use `--disable-tls-verification`.

4. Run the Ethr client

   ```bash
   ethr -c localhost -p udp -b 1M -l 1k -d 5s
   ```

You should see packets arrive at the Ethr server demonstrating that UDP tunneling is working.

## More Resources

- [Ethr](https://github.com/microsoft/ethr)