The dns module provides DNS resolution and lookup capabilities. Here's how to use it for network operations.
Basic Lookup
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Promise-based API
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Lookup Options
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Resolve DNS Records
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SOA Records
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SRV Records
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Reverse DNS Lookup
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Resolve Any Record Type
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Custom DNS Servers
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DNS Cache
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Health Check with DNS
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Error Handling
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Best Practices
Lookup vs Resolve:
✓ lookup() uses OS resolver (cached)
✓ resolve() queries DNS directly
✓ Use lookup() for general use
✓ Use resolve() for specific records
Performance:
✓ Cache DNS results
✓ Use connection pooling
✓ Set reasonable timeouts
✓ Handle failures gracefully
Error Handling:
✓ Check error.code
✓ Implement retries
✓ Log DNS failures
✓ Have fallback servers
Avoid:
✗ Hardcoding IPs
✗ Ignoring TTLs
✗ Blocking on DNS
✗ No timeout handling
Conclusion
The Node.js dns module provides comprehensive DNS resolution capabilities. Use lookup() for general hostname resolution with OS caching, and resolve*() methods for specific record types. Implement caching for performance, handle errors with retry logic, and use custom resolvers for specific DNS servers. The promises API makes async DNS operations clean and composable for modern Node.js applications.