DNS Query Worker

This repository contains a Cloudflare Worker script that performs DNS queries to multiple public DNS resolvers (Cloudflare, Google, Quad9, and AdGuard). The script periodically queries specific DNS records to verify resolver functionality and logs the results.

Features

• Periodic DNS Queries: Runs scheduled DNS queries to multiple resolvers using Cloudflare's cron trigger.
• Supported Resolvers: Includes support for Cloudflare (1.1.1.1), Google (dns.google), Quad9 (dns.quad9.net), and AdGuard (dns.adguard.com).
• Multi-server Queries: Automatically queries DNS records for multiple servers (e.g., server1.example.com, server2.example.com).
• Error Handling: Logs errors and failed responses for debugging.

Installation

1. Clone this repository:

   git clone git@github.com:vincent-cf/dns-loop.git
   cd dns-loop

2. Install the required dependencies:

   npm install

3. Authenticate with Cloudflare:

   wrangler login

4. Configure your wrangler.toml file with the appropriate settings:

   name = "dns-loop"
   main = "src/index.ts"
   compatibility_date = "2025-01-16"
   
   [[triggers.crons]]
   schedule = "*/1 * * * *"  # Run every minute
   
   account_id = "your-cloudflare-account-id"

Usage

Deploy the Worker

Deploy the script to your Cloudflare account:

wrangler deploy

Test Locally

Run the worker locally for testing:

wrangler dev

Configuration

Adding or Removing Resolvers

You can modify the resolvers array in the worker script to add or remove DNS resolvers:

const resolvers = [
  { name: "Cloudflare", url: "https://1.1.1.1/dns-query" },
  { name: "Google", url: "https://dns.google/resolve" },
  { name: "Quad9", url: "https://dns.quad9.net:5053/dns-query" },
  { name: "AdGuard", url: "https://dns.adguard.com/resolve" },
];

Changing Server List

The servers array in the script specifies which DNS records to query. Update it as needed:

const servers = Array.from({ length: 10 }, (_, i) => `server${i + 1}.your-domain.com`);

Example Logs

Successful queries will log the DNS response, while errors will log detailed messages for debugging:

DNS response from Cloudflare for server1.example.com: { ... }
Error querying server2.example.com on Google: 400 Bad Request

Contributing

Feel free to open issues or submit pull requests to improve the script or documentation.

License

This project is licensed under the MIT License. See the LICENSE file for details.