What is the difference between IPv4 and IPv6?
Answer
IPv4 uses 32-bit addresses (4 billion total) written as dotted decimal (e.g., 192.168.1.1). We are essentially out of public IPv4 addresses — NAT was a workaround. IPv6 uses 128-bit addresses providing ~340 undecillion addresses (enough to assign trillions to every person on Earth), written as colon-separated hex (e.g., 2001:db8::1). Key IPv6 improvements: no NAT needed (every device gets a unique global address), no broadcast (uses multicast/anycast), built-in IPsec, stateless address autoconfiguration (SLAAC) — devices configure themselves without DHCP, simpler header for faster routing, and better support for mobility. IPv6 header has no checksum (handled at transport layer) and no fragmentation at routers. Dual-stack deployment runs both IPv4 and IPv6 simultaneously during the transition.