DNS Client

A lightweight DNS client implementation that performs domain name to IP address translation by directly communicating with DNS servers using the DNS protocol.

Features

• Custom DNS query message construction
• UDP-based communication with DNS servers
• Support for Google's public DNS (8.8.8.8)
• Timeout-based retry mechanism
• Detailed response parsing and display
• Resource Record (RR) processing

Installation

git clone [your-repository-url]
cd dns-client

Usage

python3 main.py <hostname>

Example:

python3 main.py example.com

The client will display detailed information about the DNS resolution process, including:

• Query ID
• Response flags
• Question section details
• Answer section with resolved IP addresses
• Additional resource records (if any)

Technical Details

DNS Message Format

The implementation follows the standard DNS protocol specification (RFC 1035) with:

• Header section with query identification and flags
• Question section containing the domain name query
• Answer section in responses with resolved addresses

Retry Mechanism

• 5 second timeout for each query attempt
• Maximum 3 retry attempts
• Error reporting if no response is received

Supported Record Types

• Currently focuses on A records (IPv4 addresses)
• Future support planned for NS, MX, and CNAME records

Dependencies

• Python 3.6+
• No external libraries required (uses standard library only)

Debugging

For debugging purposes, you can use Wireshark to capture and analyze the DNS packets:

1. Start Wireshark and filter for DNS packets (filter: dns)
2. Run your query
3. Examine the packet structure and fields

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Acknowledgments

• Based on DNS protocol specifications from RFC 1035
• Uses Google's Public DNS service