Subdomain Scanner Tool

Subdomain Scanner Tool: Core Features and Principles

Website administrators often face security risks due to forgotten or abandoned subdomains. This tool aggregates public DNS records and web indexes to quickly scan all active subdomains under a target domain, outputting a standardized subdomain list. A subdomain refers to the third-level (or higher) domain identifier located before the main domain, such as "mail" in mail.example.com.

Why Choose Our Subdomain Scanner?

• Supports naked domains or URLs with protocols, adapting to different use cases.
• Outputs results as a standardized plain text list for easy copying and processing.
• Requires no registration or complex configuration; get key security assessment data in under 30 seconds.

How to Use

1. Enter the target domain (e.g., example.com) into the input box.
2. Click the "Scan" button to start the process.
3. View the resulting list of subdomains in the text box.

Frequently Asked Questions (FAQ)

Q: Can the tool detect unpublished internal subdomains?
A: No. This tool relies on public data sources and only returns subdomains that can be resolved via DNS.

Q: Is there a difference between entering www.example.com and example.com?
A: The system automatically strips the "www" prefix, so both inputs will yield the exact same scan results.

Important Notes

Please ensure you enter the correct domain format (naked domains are recommended). The results may miss unpublished subdomains. Do not use this tool for illegal scanning. Please be patient when scanning large domains.

Technical Notes & Best Practices

We recommend regularly scanning your own domains, paying special attention to non-production subdomains like "test" or "dev". Example: Entering example.com might return subdomains such as www, mail, and blog.