IPv4

    The most widely used version of IP addressing based on 32-bit.

    IPv4 (Internet Protocol version 4) is the most widespread protocol for addressing and routing packets between devices in IP networks. Each IPv4 address is 32-bit long and written as four decimal numbers separated by dots (dotted-decimal), for example 192.168.1.1. This provides a theoretical address space of approximately 4.3 billion unique addresses.

    The IPv4 header contains source and destination addresses, TTL (Time To Live), protocol type and fragmentation fields. Packets are routed based on the destination address.

    The address space is divided into public and private ranges. RFC 1918 defines three private address blocks: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. These are used in local networks behind NAT (Network Address Translation). IPv4 exhaustion is driving the transition to IPv6.

    Points clés

    • 32-bit addresses provide ~4.3 billion unique addresses
    • Written in dotted-decimal: e.g. 192.168.1.1
    • Private addresses defined in RFC 1918 (10.x, 172.16.x, 192.168.x)
    • NAT is used to share public addresses between multiple devices
    • Address exhaustion is driving the transition to IPv6

    Termes associés

    IPv6SubnetCIDRIP AddressASNBGPAnycastNATPAT

    Outils associés

    What is my IPSubnet / CIDR Calculator