PacketStreamNAT (Network Address Translation)
NAT maps addresses and ports between networks, commonly allowing several private devices to share one public IP address. NAT stands for Network Address Translation and is widely used at the boundary between a home network and the public internet.
When a device opens an outbound connection, a home router replaces the device’s private source address with the router’s public address. It records a mapping that includes transport ports so returning packets can reach the correct device. To an internet destination, connections from phones, computers, and other devices in that home can all appear to come from the same public IP.
This mapping also means unsolicited inbound connections usually have no internal destination unless the router has a port-forwarding rule or another traversal mechanism. NAT is not the same as a firewall, even though both can affect whether inbound traffic reaches a device. Its primary job is translating addressing information and tracking flows across the boundary.
Carrier-grade NAT applies the sharing model inside an internet provider, placing multiple subscribers behind public addresses. For a residential proxy, the exit node’s translated public address is the source a destination records.