Reserver IP Addresses

Private IP addresses

  • Private IP address ranges
    • IPv4 address ranges:
      • -
      • -
      • -
    • IPv6 address range
      • fd--::/8
  • Cannot be used or routed on the internet
  • Helps delay IPv4 address exhaustion
  • Used in local area networks (LAN)
  • Provides flexible IP ranges for larger or smaller private networks
  • Allow for additional subnets within the ranges

Loopback IP address

  • IP address range/IP address:
    • (IPv4) -
    • (IPv6) ::1/128
  • Reserved for a Host's self address (or localhost address)
  • Managed by the operating system
  • Does not utilize the network interface card (NIC)
  • Uses a virtual network interface within the operating system
  • Can be used for testing on the local machine

Ling-local Addresses

  • IP address range:
    • (IPv4) -
    • (IPv6) fe80::/10
  • Used in the absence of DHCP or static addresses
  • Can only communicate within its own network segment
  • Routers will not forward packets from a loopback address
  • Uses Address Resolution Protocol (ARP) to ensure that the desired IP address is not in use
  • IPv6 requires a link-local address even if a routable address has been assigned

Unspecified Address

  • (IPv4)
  • (IPv6) ::