What is the purpose of a link-local address?

These addresses refer only to a particular physical link and are used for addressing on a single link for purposes such as automatic address configuration and neighbor discovery protocol. Link-local addresses can be used to reach the neighboring nodes attached to the same link.

How link-local address is generated?

The IPv6 Link Local addresses are made from the first 64-bit reservation (FE80::/64) and remaining bits are taken from the MAC address of the interface. But, MAC addresses are 48 bit numbers. 64+48 is only 112bits to form IPv6 address (IPv6 addresses are 128 bit in length).

What do link local addresses start with?

FE80
You can see the format of the link-local address below. It starts with FE80 and is followed by 54 bits of zeros. Lastly, the final 64-bits provide the unique Interface Identifier.

Why do I have a link-local IPv6 address?

IPv6 link-local addresses are addresses that can be used to communicate with nodes (hosts and routers) on an attached link. Packets with those addresses are not forwarded by routers. At least, they should not be. There have been cases where routers would happily forward packets with a link-local source address.

Is it normal to have 2 IPv6 addresses?

A device generates new 64 bits every once in a while and uses that in the IPv6 address. Because new addresses are generated regularly the addresses are marked as temporary . A device can have multiple privacy extension addresses if the system is still using an old address when a new address is being generated.

How do I find my IPv6 link local address?

Configuring a link-local IPv6 address on an interface

1. Enter global configuration mode. device# configure terminal.
2. Enter interface configuration mode. device(config)# interface ethernet 3/1.
3. Configure a link-local IPv6 address for the interface. device(config-if-e1000-3/1)# ipv6 address FE80::240:D0FF:FE48:4672 link-local.

What do you mean by link local address?

Firs, link-local address is alway an IP address. Not always, most commonly people do mean a link-local IP addresses when they use the term. When they mean this the addresses are always IP addresses, either IPv4 or IPv6.

Why are link local addresses required in IPv6?

In IPv6, link-local addresses are mandatory and required for the internal functioning of various protocol components. Automatic address configuration of link-local addresses is often non-deterministic as the resulting address cannot be predicted.

How are link local addresses assigned in Internet Protocol 4?

From this block, the address range 169.254.0.1 to 169.254.255.254 may be used for link-local addressing in Internet Protocol Version 4. Link-local addresses are assigned to interfaces by host-internal, i.e. stateless, address autoconfiguration when other means of address assignment are not available.

Can a MAC address be a link local address?

Not always, most commonly people do mean a link-local IP addresses when they use the term. When they mean this the addresses are always IP addresses, either IPv4 or IPv6. It is valid in some circumstances to refer to a MAC address as a link-local address but it is a less common use of the term.