For IT leaders
NAT is the reason most internal IPv4 schemes work; understanding it stops a lot of false-positive 'firewall is broken' tickets.
Why IT teams care
Where this shows up at the team level
- Site-to-site VPN, cloud connectivity, and partner integrations frequently break on overlapping or misconfigured NAT.
- Public-facing services rely on destination NAT (DNAT) and load-balancer translations.
- Modern hybrid stacks add NAT layers (cloud NAT gateways, container egress) that on-prem-trained engineers may not recognize.
In production
Where teams encounter it
- Edge routers and firewalls translating private space to a public IP
- Cloud NAT gateways for outbound traffic from private subnets
- Site-to-site VPNs and partner B2B links with overlapping address ranges
How it works
How NAT actually works
- 01A NAT device tracks a translation table that maps internal address/port pairs to external address/port pairs.
- 02Static NAT maps one internal address to one external address; dynamic NAT and PAT (overload) share one external address across many internal hosts using port numbers.
- 03Destination NAT redirects inbound traffic to internal hosts; commonly used for publishing services behind a firewall.
- 04NAT preserves the public IPv4 space and adds an implicit privacy layer, but it complicates protocols that embed addresses in payloads.
In practice
Common team use cases
- Letting many internal devices share a small block of public IPs
- Publishing internal applications via DNAT or load balancers
- Bridging environments with overlapping RFC 1918 address space
Build the capability
Related CBT Nuggets training
Each link routes to a hub that goes deeper than this definition.
Related concepts