What is the point of private IP
What is the point of private IP
You're asking about how networks organize addresses. Each device gets a private IP for internal communication, while the public IP handles external connections. The private IP isn't just for devices—it helps route traffic correctly. Logging packets by MAC address with port numbers simplifies routing without needing unique IDs for every device. It's more efficient and keeps the network organized.
IP networking originally wasn't built with connecting private networks to public ones in mind; NAT became a workaround. Once everyone needed internet access, it became impractical and risky. Companies using leased lines had strict firewalls, but as demand grew, we shifted to NAT routers that could manage private IPs within businesses, conserving IPv4 addresses. IPv6 was designed differently—every device gets a public IP, yet routers block traffic by default unless allowed.
They serve distinct purposes. MAC addresses are tangible identifiers used by network equipment to route data packets. IP addresses function as abstract labels for organizing and sending traffic. Only a finite number—about 4.3 billion—are available, encompassing both standard and special-use formats. In the past, vast swaths of IP addresses were reserved for big companies or military use, creating scarcity as the web expanded beyond academic settings. NAT and private address ranges help accommodate more devices by allowing multiple connections under a single IP. Additionally, some older networking protocols ignore MAC addresses altogether, or tolerate duplicate ones, yet still support TCP/IP communication.
MAC addresses work at the second layer for sending data within the same network segment. Switches rely on these addresses to direct traffic (I’ll skip L3 switches that handle routing). IP addresses function at the third layer, moving packets across different segments. Routers depend on IP addresses to route traffic between networks.