NAT (Network Address Translation) is a method that maps multiple private IP addresses to one or more public IP addresses. It allows many devices on a local network to share a single public IP when accessing the internet.
A NAT device (usually a router) sits between a private network and the internet. When an internal device sends a request, the router replaces the private source IP with its public IP and tracks the mapping in a translation table. When the response arrives, the router uses the table to forward the data back to the correct internal device.
Most proxy users only need to understand this well enough to debug it, not configure it directly.
USER-country-de-session-task01The username carries the config: "country-de" picks the exit, "session-task01" holds it in place while NAT does its work underneath. No separate API call or handshake -- the label is the setting.
Measure this metric without a proxy first, so you know what the gateway adds versus what was already there.
This concept governs the connection to the gateway and the gateway to the target -- check both when something looks wrong.
KnoxProxy manages this at the infrastructure layer, so most jobs only need to understand it well enough to debug.
A new ISP, VPN, or office network can change how this behaves -- confirm it again after any local network change.
In your home, your phone, laptop, and smart TV all share one public IP address through your router NAT, even though each has its own private IP (192.168.1.x).
NAT is why millions of devices can share limited IPv4 addresses. Understanding NAT helps you grasp why CGNAT mobile IPs are trusted and why your home IP represents all your devices.
NAT provides a basic level of obscurity by hiding internal IP addresses from the internet. However, it is not a firewall and does not inspect or filter traffic. It should not be relied on as a security measure.
Regular NAT happens at your router, mapping your home devices to one public IP. CGNAT (Carrier-Grade NAT) adds another layer at the ISP level, mapping many customers to a shared pool of public IPs.
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