Understanding IP Addresses

IPv4 Address Format

IPv4 addresses consist of four octets (numbers from 0-255) separated by dots. Each octet represents 8 bits, making IPv4 addresses 32 bits total.

IPv4 Address Classes:
  • Class A: 1.0.0.0 - 126.255.255.255 (Large networks)
  • Class B: 128.0.0.0 - 191.255.255.255 (Medium networks)
  • Class C: 192.0.0.0 - 223.255.255.255 (Small networks)
  • Class D: 224.0.0.0 - 239.255.255.255 (Multicast)
  • Class E: 240.0.0.0 - 255.255.255.255 (Reserved)
Private IP Ranges:
  • 10.0.0.0/8 - 10.0.0.0 to 10.255.255.255
  • 172.16.0.0/12 - 172.16.0.0 to 172.31.255.255
  • 192.168.0.0/16 - 192.168.0.0 to 192.168.255.255

IPv6 Address Format

IPv6 addresses are 128 bits long and written as eight groups of four hexadecimal digits, separated by colons. They can be compressed using double colons (::) to represent consecutive zeros.

IPv6 Address Types:
  • Unicast: Identifies a single interface
  • Multicast: Identifies multiple interfaces (starts with ff)
  • Link-Local: Used on single network segment (fe80::/10)
  • Unique Local: Private addresses (fc00::/7)
IPv6 Notation Examples:
  • Full: 2001:0db8:0000:0000:0000:0000:0000:0001
  • Compressed: 2001:db8::1
  • Mixed: 2001:db8::192.168.1.1

Try These Examples

Valid IPv4 Addresses
Valid IPv6 Addresses