IPv6 Link-Local Calculator
Derive the fe80::/10 link-local address a host will use from its MAC address, with the zone identifier.
Inputs
Link-Local Address
fe80::21a:2bff:fe3c:4d5e
Scoped Address
fe80::21a:2bff:fe3c:4d5e%eth0
Solicited-Node Multicast Address
ff02::1:ff3c:4d5e
Prefix
fe80::/10
Step by step
Values used
MAC address = 00:1a:2b:3c:4d:5e; Interface / zone name = eth0
IPv6 Link-Local
The fe80::/64 prefix is combined with the modified EUI-64 interface identifier derived from the MAC address.
Link-Local Address
= fe80::21a:2bff:fe3c:4d5e
Scoped Address
= fe80::21a:2bff:fe3c:4d5e%eth0
Solicited-Node Multicast Address
= ff02::1:ff3c:4d5e
Prefix
= fe80::/10
How it works
Link-local addresses are formed automatically on every IPv6 interface from the fe80 prefix plus an interface identifier. Because the same address can exist on several links, a zone identifier selects the interface. The solicited-node multicast address is derived from the last 24 bits and is what neighbour discovery targets. Link-local addresses are what routing protocols such as OSPFv3 and BGP peer over, so predicting them is routine when building or troubleshooting adjacencies.
Formula
IPv6 Link-Local
The fe80::/64 prefix is combined with the modified EUI-64 interface identifier derived from the MAC address.
- fe80::/10
- Reserved link-local prefix
- %zone
- Interface selector required because link-local addresses are ambiguous
Frequently Asked Questions
How is IPv6 Link-Local calculated?
The fe80::/64 prefix is combined with the modified EUI-64 interface identifier derived from the MAC address. Link-local addresses are formed automatically on every IPv6 interface from the fe80 prefix plus an interface identifier. Because the same address can exist on several links, a zone identifier selects the interface. The solicited-node multicast address is derived from the last 24 bits and is what neighbour discovery targets.
Why does IPv6 Link-Local matter?
Link-local addresses are what routing protocols such as OSPFv3 and BGP peer over, so predicting them is routine when building or troubleshooting adjacencies.
What values do I need to enter?
This calculator takes 2 inputs: MAC address, Interface / zone name. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.