Free Subdomain Finder

Discover hidden subdomains for bug bounty hunting and penetration testing. Find attack surface and potential security vulnerabilities.

🔍 Find Subdomains

Enter a domain name without http:// or www. (e.g., example.com)
Legal Notice: Only scan domains you own or have explicit permission to test.

What is Subdomain Enumeration?

Subdomain enumeration is the process of discovering all subdomains associated with a domain. Subdomains often host different services, applications, or environments that may have different security configurations, making them valuable targets for security testing.

Why Find Subdomains?

  • Expand Attack Surface: Discover more potential entry points for testing
  • Find Forgotten Services: Legacy or development servers often have weaker security
  • Bug Bounty: Many programs reward findings on any subdomain
  • Reconnaissance: Essential first step in penetration testing
  • Asset Discovery: Identify all digital assets owned by an organization

Common Subdomain Patterns

Pattern Example Typical Purpose
www www.example.com Main website
api api.example.com API endpoints
dev, staging dev.example.com Development/Testing
mail, smtp mail.example.com Email servers
admin, panel admin.example.com Admin interfaces
Security Tip: Always ensure subdomains have proper security configurations. Development and staging environments are common targets for attackers.

Subdomain Finder FAQs

Subdomain enumeration using passive methods (like DNS lookups) is generally legal. However, always ensure you have permission to test any systems you discover. Many bug bounty programs explicitly allow subdomain enumeration within their scope.

Subdomain enumeration uses various techniques: DNS brute forcing (trying common names), certificate transparency logs, search engine dorking, and third-party databases. Our tool uses a combination of these methods to discover subdomains.

After finding subdomains, you can: 1) Check if they're live and accessible, 2) Run port scans to identify services, 3) Check for vulnerabilities, 4) Look for sensitive information disclosure, 5) Test authentication mechanisms.