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Network Spaces AKA Reserved IP Ranges

Private Addresses

IPv4

→ See Wikipedia - Private IPv4 Addresses

RFC 1918 name IP address range Number of addresses Largest CIDR block (subnet mask) Host ID size Mask bits Classful description
24-bit block 10.0.0.0 – 10.255.255.255 16777216 10.0.0.0/8 (255.0.0.0) 24 bits 8 bits single class A network
20-bit block 172.16.0.0 – 172.31.255.255 1048576 172.16.0.0/12 (255.240.0.0) 20 bits 12 bits 16 contiguous class B networks
16-bit block 192.168.0.0 – 192.168.255.255 65536 192.168.0.0/16 (255.255.0.0) 16 bits 16 bits 256 contiguous class C networks

IPv6

→ See Wikipedia - Private IPv6 Addresses

Other Addresses & Ranges

The validity of link-local addresses is limited to a single link; e.g. to all computers connected to a switch, or to one wireless network. Hosts on different sides of a network bridge are also on the same link, whereas hosts on different sides of a network router are on different links.

See → Wikipedia - Link-Local Addresses

  • Covers IPv4, IPv6, and the loopback interface(s) for each.
  • Loopback Interfaces
    • IPv4 → The entire class A block of 127.0.0.0/8
    • IPv6 → ::1