Nearly all internet traffic today still passes through IPv4. Although IPv6 migration is active due to exhaustion, IPv4 remains central. Learn how IPv4 lookup works and the mechanisms behind it.
IPv4 uses 32-bit addresses, allowing about 4.29 billion unique addresses in theory. That seemed ample in the 1980s, but the smartphone and IoT era brought full exhaustion. Engineers worldwide extended IPv4's life by combining private IPs with NAT as a workaround.
Your home router receives only one public IPv4 from your ISP and assigns private IPv4 addresses (192.168.x.x) to connected devices. When an internal device requests Google, the router replaces the private source IP with its single public IP, records the port, and forwards the packet. When Google's reply returns, it translates back to the correct private IP. This address translation is NAT, allowing dozens of devices to share one public IP.
Windows settings may show 192.168.x.x or 10.x.x.x, while U-Star IP shows something like 210.x.x.x. The former is a private IPv4 valid only inside the router; the latter is the unique public IPv4 the website uses to identify and respond to you. For game servers, firewall rules, and external access, always use the public IPv4 shown on the website.