Link-local address

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Link-local addresses are network addresses which are intended only for use in a local data link layer network, and not for routing beyond that network.

Link-local addresses are often used for network address autoconfiguration where no external source of network addressing information is available.

An example of this use of link-local addressing is the automatic configuration of IP addresses which is used in both IPv4 and IPv6. IPv4 addresses in the range from 169.254.0.0 to 169.254.255.255 are assigned when no other IP addressing assignment is available, e.g. no connectivity to a DHCP server.

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[edit] IPv4

Based on RFC 3927, IPv4 uses the 169.254.0.0/16 (link-local) range of addresses. In the RFC the technique for IPv4 is called IPv4 Link-Local (IPV4LL). Microsoft refers to this as Automatic Private IP Addressing (APIPA) or Internet Protocol Automatic Configuration (IPAC).

[edit] IPv6

For IPv6 autoconfiguration is based on RFC 2462.

[edit] Stateless autoconfiguration

Allows an IPv6 host to obtain a unique address using the IEEE 802 MAC address.

[edit] Stateful autoconfiguration

An IPv6 host uses a DHCPv6 server which keeps a record of the IP address and other configuration information for the host.

[edit] Combined Stateless and Stateful

Used with the Managed Address Configuration and Other Stateful Configuration flags in the ICMPv6 Router Advertisement messages.

[edit] See also

[edit] External links

  • RFC 3484 — default Address Selection for Internet Protocol version 6 (IPv6)