Networking

IP addresses, DNS, TCP/UDP, Wi-Fi and how data actually moves.

How DNS Works: From Root Servers to an IP Address, Step by Step
Follow a real DNS lookup with nslookup: resolver, root, .com and authoritative servers, the A, AAAA, CNAME, MX, TXT and NS record types, and how TTL caching works.
Public vs Private IP Address: Ranges, NAT and How to Find Yours
The exact private IPv4 ranges (RFC 1918), how NAT and CGNAT share a public address, what 127.x and 169.254.x mean, and how to find yours on any OS.
TCP vs UDP: Differences, Header Sizes and What Uses Which
TCP sets up a connection and guarantees ordered delivery; UDP sends datagrams with no guarantees. Handshake, 20 vs 8 byte headers, and why HTTP/3 and DNS use UDP.