nslookup is a network administration tool for querying DNS servers to obtain domain name or IP address mapping information. While considered legacy in some contexts, it remains widely used due to its simplicity and availability across platforms.
Key Features
DNS record querying
Reverse DNS lookups
Interactive query mode
Server selection
Multiple record type support
Cross-platform compatibility
Installation
Ubuntu (22.04/24.04)
macOS
Basic Usage
Simple Queries
Command Format
Query Types
Common Record Types
Multiple Record Query
Interactive Mode
Basic Interactive Commands
Interactive Mode Options
Server Selection
Advanced Options
Debug Options
Query Control
Output Control
Troubleshooting
Common Issues
DNS Resolution Problems
Reverse DNS Issues
Connection Problems
Debug Mode
Best Practices
DNS Server Testing
Record Verification
Security Checks
Quick Reference
Essential Commands
Common Options
Interactive Mode Commands
Examples for Common Tasks
Mail Server Verification
Domain Configuration
Security Checks
Remember:
Always verify critical DNS records
Use multiple DNS servers for validation
Document query results
Consider using modern alternatives (dig) for advanced tasks
Keep timeout values reasonable
For more detailed information, consult the man pages (man nslookup).