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What is IPv4 and IPv6?

Some regional networks run on older IPv4 systems

Written by Michael Cioni


What happens if an ISP isn't IPv6?


IPv4 (Internet Protocol version 4)

  • Uses 32-bit addresses, written as four numbers (e.g., 192.168.1.1)

  • Supports about 4.3 billion unique addresses

  • Has been the backbone of the internet since the early 1980s

  • Relies heavily on NAT (Network Address Translation) because addresses ran out

  • Still widely used, but increasingly strained

IPv6 (Internet Protocol version 6)

  • Uses 128-bit addresses, written in hexadecimal (e.g., 2001:0db8:85a3::8a2e:0370:7334)

  • Supports an enormous number of addresses (enough for virtually every device on Earth)

  • Designed to reduce or eliminate the need for NAT

  • Includes built-in support for security (IPsec) and auto-configuration

  • Better suited for IoT, mobile devices, and peer-to-peer networking

Why this matters (especially for P2P)

IPv6 makes it much easier for devices to connect directly to each other, which improves peer-to-peer applications like real-time communication, decentralized networks, and autonomous systems. IPv4, by contrast, often forces traffic through intermediaries because of NAT, adding latency and complexity.

In short:

  • IPv4 = older, limited address space, still dominant

  • IPv6 = modern, massively scalable, designed for today’s connected world

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