Caddy Defender Plugin

The Caddy Defender Plugin serves as an effective middleware solution for the Caddy web server, enabling users to block or manage requests based on client IP addresses. This feature is particularly valuable for preventing unwanted bot traffic and protecting website data from being used for AI training, by returning non-informative or corrupted responses.

Features

• IP Range Filtering: Block or change requests originating from specified IP ranges.
• Embedded IP Ranges: Utilizes predefined IP ranges for commonly used AI services such as OpenAI and GitHub Copilot.
• Custom IP Ranges: Allows for the addition of personalized IP ranges via straightforward Caddyfile configuration.
• Multiple Responder Backends:
  • Block: Delivers a 403 Forbidden response to the request.
  • Garbage: Returns nonsensical data, disrupting AI training models.
  • Custom: Offers the ability to return a tailored message.

Configuration

The Caddyfile directive provides a simple syntax to set up the defender plugin, optimizing control over traffic management.

defender <responder> {
    message <custom message>
    range <ip_ranges...>
}

Where:

• <responder> expresses the action to take, with options such as block, garbage, or custom.
• <ip_ranges...> includes CIDR ranges or predefined keys (e.g., openai).
• <custom message> specifies any returned message when using the custom responder.

Usage Examples

Block Requests

To block requests from certain IP ranges:

localhost:8080 {
    defender block {
        range 203.0.113.0/24 openai 198.51.100.0/24 
    } 
    respond "Hello, world!" # Response for users
}

Return Garbage Data

To return corrupted responses for specific IP ranges:

localhost:8081 {
    defender garbage {
        range 192.168.0.0/24 
    }
    respond "Hello, world!" # Response for users
}

Custom Response

To provide a custom message for requests from designated IP ranges:

localhost:8082 {
    defender custom {
        message "Custom response message"
        range 10.0.0.0/8
    }
    respond "Hello, world!" # Response for users
}

Embedded IP Ranges

The plugin incorporates predefined IP ranges for several prominent AI services, allowing users to employ them without additional configuration:

Contributing

Contributions are welcomed. Those interested in adding new IP ranges or responder functionalities can find more information in the Contributing Guide.

Acknowledgments

Inspired by discussions within the community, this project is built on top of the well-regarded Caddy. For those interested in observing the project's growth, please view the Star History.