Project Overview

This is a custom DNS resolver built in Node.js for educational purposes. It constructs DNS query packets, sends them to a DNS server, and parses the responses to resolve domain names into IP addresses. A simple web interface is included to make the program user-friendly.

Features

• Resolves domain names to IP addresses using UDP.
• Custom packet construction and parsing.
• Frontend interface to input domain names and display results.
• Error handling

Getting Started

1. Prerequisites:

• Node.js installed.
• Basic understanding of DNS.

2. Installation:

git clone https://github.com/kaylamoorcroft/dns-resolver
cd dns-resolver
npm install

3. Running the App:
   npm start

Usage

• Open the browser and navigate to http://localhost:3000.
• Input a domain name (e.g., www.example.com) and click "Resolve domain"
• The resolved domain name will appear. Or if an error occurs, you will see an error message instead.
• Console logs in the terminal will provide DNS resolution details such as the DNS query and response packets.

Project Structure

project-root/  
├── public/  
│   ├── style.css       # Frontend styles  
│   ├── script.js       # Frontend JavaScript  
├── views/  
│   ├── index.html      # Main HTML file  
├── server.js           # Backend code  
├── package.json        # Dependencies and scripts  
├── package-lock.json   # Locked versions of dependencies  
├── README.md           # Project documentation

How It Works

• Creates a DNS query packet in binary.
• Sends the query to a DNS server (Google DNS at 8.8.8.8) over UDP using a socket.
• Listen for a response and parses it to extract the IP address.
• Displays the IP address or an error on the frontend.

Technologies Used

• Node.js
• Express
• Dgram (for UDP socket)
• JavaScript (Frontend and Backend)
• HTML/CSS

Future Improvements

• Turn this into a recursive resolver by querying multiple servers in the DNS server hierarchy
• Add support for other DNS record types such as AAAA (IPv4 addresses) or MX (mail servers)