Deep Packet Inspection (DPI) examines packet payloads, not just headers. While standard firewalls check source, destination, and port, DPI reads the actual data being transmitted.
DPI enables:
- Malware detection in file transfers
- Data loss prevention (blocking sensitive data leaving the network)
- Protocol validation (ensuring HTTPS traffic is actually HTTPS)
- Content filtering (blocking inappropriate content)
The tradeoff is performance. DPI requires significant processing power. High-traffic networks need appropriately sized hardware.