## Definition A unique 32-bit address to identify a device on a network; used for routing packets across networks. *Noun.* > The IPv4 address of my Minecraft server is `82.31.19.128`. ## Characteristics - Part of the [[Internet Protocol]]; - used at the [[network layer]] of the TCP/IP stack; - is 32 bits long; - there are around 4 billion possible unique addresses; - usually represented in denary: - written as four separate groups of eight bits (called octets); - each denary number is separated by `.`s; and - each denary number must be between 0 and 255 inclusive. ## Examples - `0.0.0.0` - `255.255.255.255` - `192.168.0.1` ## Non-examples ### Invalid IPv4 addresses These break the rules of IPv4 addresses: - `256.128.90.74` (first number is > 255); - `-100.128.90.74` (first number is < 0); - `192:168:1:0` (separated by `:`, not `.`); and - `192.168.0.1.128` (five denary numbers, not four). ### MAC addresses [[MAC address|MAC addresses]] are unique hardware identifiers used for routing packets on a single network. ### IPv6 addresses [[IPv6 address|IPv6 addresses]] are a newer iteration of IP addresses using 128 bits rather than 32.