Resolver

A high-performance, concurrent domain name resolver tool written in Go. This tool efficiently resolves domain names to IP addresses, handling various URL formats and providing flexible output options.

Features

• Concurrent resolution for high performance
• Handles various URL formats (with or without http/https, www prefix, etc.)
• Two output formats: IP-only (default) and domain-IP mapping
• Removes duplicate IPs in the default output mode
• Customizable concurrency level
• Simple command-line interface

Installation

1. Ensure you have Go installed on your system. If not, download and install it from golang.org.

2. Install the resolver tool using the following command:

   go install github.com/harshinsecurity/resolver@latest
   

3. Make sure your Go bin directory is in your system's PATH.

Usage

Basic usage:

resolver

This will use default settings: reading from urls.txt, writing to resolved_ips.txt, using 100 concurrent workers, and outputting unique IPs only.

Command-line Options

• -input: Specify the input file (default: "urls.txt")
• -output: Specify the output file (default: "resolved_ips.txt")
• -concurrency: Set the number of concurrent workers (default: 100)
• -format: Choose the output format: "ip" (default) or "domain-ip"
• -help: Display help information

Examples

1. Use custom input and output files:

   resolver -input=my_domains.txt -output=results.txt
   

2. Increase concurrency to 200 workers:

   resolver -concurrency=200
   

3. Output domain-IP mappings instead of just IPs:

   resolver -format=domain-ip
   

4. Combine multiple options:

   resolver -input=sites.txt -output=ips.txt -concurrency=150 -format=domain-ip
   

Input File Format

The input file should contain one URL or domain per line. The tool can handle various formats:

example.com
http://example.com
https://www.example.com
https://subdomain.example.com/path

Output Formats

1. IP-only (default):

   • Outputs only unique, successfully resolved IP addresses
   • One IP per line
   • Unresolved domains are skipped

2. Domain-IP mapping:

   • Outputs "domain,ip" for resolved domains
   • Outputs "domain,Could not resolve" for unresolved domains

Development

If you want to contribute or modify the tool, you can clone the repository and build it locally:

git clone https://github.com/harshinsecurity/resolver.git
cd resolver
go build

Contributing

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

License

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