NAT breaks end-to-end connectivity:
Connection initiation:
- Devices behind NAT can't receive unsolicited inbound connections
- Peer-to-peer applications struggle
- Hosting services requires extra configuration
Protocol issues:
- Some protocols embed IP addresses in payloads
- NAT only translates headers
- FTP, SIP, and gaming protocols often break
Performance overhead:
- Every packet needs header modification
- Translation table lookups add latency
Troubleshooting complexity:
- IP addresses in logs don't match actual devices
- Multiple users share one public IP