The dns module provides DNS resolution and lookup capabilities. Here's how to use it effectively.
Basic Lookups
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IP Version Options
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DNS Resolution
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Generic Resolution
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Reverse DNS Lookup
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Custom DNS Servers
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Error Handling
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Caching DNS Results
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Practical Examples
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Best Practices
Usage:
✓ Use dns.promises for async/await
✓ Handle all error codes appropriately
✓ Implement caching for repeated lookups
✓ Use custom resolvers when needed
Performance:
✓ Cache DNS results with appropriate TTL
✓ Use parallel resolution when possible
✓ Consider using faster DNS servers
✓ Implement timeouts
Security:
✓ Validate hostnames before lookup
✓ Use DNSSEC when available
✓ Be aware of DNS rebinding attacks
✓ Log suspicious DNS queries
Avoid:
✗ Blocking the event loop with sync calls
✗ Ignoring DNS errors
✗ Hardcoding DNS servers in production
✗ Making DNS calls in hot paths
Conclusion
The dns module provides comprehensive DNS functionality for Node.js. Use dns.promises for modern async/await code, implement caching for performance, and handle errors appropriately. Consider using custom resolvers for specialized DNS requirements.