NAT provides several benefits beyond address conservation:
Address conservation:
- Thousands of devices share one public IP
- Extends IPv4's usable life
- Reduces public IP costs
Security through obscurity:
- Internal network structure hidden
- Attackers can't directly reach private addresses
- Acts as basic firewall (blocks unsolicited inbound)
Network flexibility:
- Change ISPs without renumbering internal devices
- Merge networks without IP conflicts
- Use any private addressing internally
These advantages explain why NAT remains popular even as IPv6 grows.