# deno-no-ipv4-here
*Inspired by [ungleich](https://code.ungleich.ch/ungleich-public/ungleich-no-ipv4-here)*

A simple microservice that responds the following text to all requests

```
Sorry, (this part of) domain $domain is not reachable by IPv4. Please upgrade to IPv6 and try to reach $domain again.
```

Written for Deno.

## Enable for your site

Simply add the A record `82.153.138.10` to your domain besides your existing AAAA record to use the version hosted by us.

If you want to host it yourself, run: 

`docker run -d --name no-ipv4-here -e SERVICE_DOMAIN=no-ipv4-here.YOUR-DOMAIN.com -p 8080:8080 --restart unless-stopped git.kyun.li/gunter/no-ipv4-here:latest`

or read on.

## Configuration

The application uses the following environment variables:

- `SERVICE_DOMAIN`: The domain where this service is hosted (default: "localhost")
  - Example: `SERVICE_DOMAIN=no-ipv4-here.example.com`

When making requests to this service, the domain you provide in the `back_to` parameter will be compared against this value to determine if it should be treated as an external domain.

## Running with Deno

1. Install Deno: https://deno.land/manual/getting_started/installation
2. Clone this repository:
   ```bash
   git clone https://git.kyun.li/gunter/deno-no-ipv4-here
   cd deno-no-ipv4-here
   ```
3. Start the service:
   ```bash
   deno run --allow-net --allow-read app.ts
   ```
4. Set the SERVICE_DOMAIN environment variable for your domain:
   ```bash
   SERVICE_DOMAIN=your-domain.example.com deno run --allow-net --allow-read app.ts
   ```

## Running with Docker

1. Build the Docker image:
   ```bash
   docker build -t deno-no-ipv4-here .
   ```
2. Run the container with your domain configuration:
   ```bash
   docker run -e SERVICE_DOMAIN=your-domain.example.com -p 8080:8080 deno-no-ipv4-here
   ```

## Example Caddy Configuration

Here's a Caddyfile configuration that redirects all non-configured domains to this service:

```caddy
# Caddyfile
(your_domain) {
    # Your existing configuration for your domain
    reverse_proxy localhost:8080
}

# Catch-all for all other domains
:80, :443 {
    # Redirect to the no-ipv4-here service
    redir https://no-ipv4-here.your-domain.example.com?back_to={host} permanent
}
```

This configuration:
1. Handles requests for your configured domain normally
2. Redirects all other domains to the no-ipv4-here service
3. Passes the original host as the `back_to` parameter
4. Uses a permanent redirect (HTTP 301)

Replace `no-ipv4-here.your-domain.example.com` with the domain where you're running this service.