Network Address Translation (NAT) is a technique routers use to translate addresses as traffic crosses between networks. In a typical home, every device has a private address, but the household often shares one public IPv4 address when connecting to websites. NAT helps keep track of those connections so replies return to the correct device.
A simple example
Imagine a laptop at 192.168.1.20 and a phone at
192.168.1.21 both visiting the same website. The router
translates each outgoing connection to its public address and records
enough connection information to send each reply back to the originating
device. The website usually sees the router’s public IPv4 address rather
than the two private addresses.
This is why your phone, television, and laptop can show the same public IP when they use one home Wi-Fi network. Their local addresses are different, but their traffic exits through the same internet connection.
NAT types and related terms
Home routers commonly perform network or port address translation. In practice, the router tracks connections and ports, allowing many private devices to reuse one public address. Carrier-grade NAT (CGNAT) adds a similar shared layer inside an ISP’s network, so multiple customers may share an outward-facing IPv4 address. NAT terminology varies, and different products may label behaviors differently.
NAT is not a firewall
NAT often means unsolicited inbound connections do not have an established mapping to a local device, which limits certain kinds of direct reachability. But NAT is not a general security policy. A router may still have exposed administration services, weak credentials, unsafe port forwards, or outdated firmware. Firewall rules, updates, and authentication are separate and necessary protections.
When NAT matters
NAT can affect online gaming, peer-to-peer connections, hosting a server at home, remote camera access, and voice or video applications. If an app reports a “strict” NAT type, the issue may relate to router behavior, carrier-grade NAT, or the app’s connectivity method. Port forwarding is not always the right fix and can expose services to the internet. Prefer the application’s recommended safe connection method and avoid opening ports you do not understand.
How to identify your situation
- Check the public IP shown by the KiwiVPN checker.
- Compare it with the WAN or Internet IP shown in your router’s administration interface.
- If they differ, your ISP may use CGNAT or another upstream gateway.
- Ask your provider whether inbound connections are supported before configuring port forwarding.
- Keep the router’s admin interface off the public internet unless a secure, explicitly needed management method is configured.
Common questions
Does NAT hide my device from every attacker?
No. It changes address and port handling. Malware, phishing, weak passwords, exposed services, and compromised accounts remain possible risks.
Can I have NAT with IPv6?
IPv6 is designed to reduce the need for address translation, but some networks and deployments use translation technologies. A firewall is still important regardless of protocol.
Why do several devices show the same public IP?
They commonly share the router’s internet connection, which translates their traffic to one public IPv4 address.
Related KiwiVPN guides
Continue with Public and private IP addresses, Carrier-grade NAT, and Router security checklist.
Further reading
Browse all KiwiVPN guides or return to the public IP checker.