Hello John,

the FE80::/10 are the link local addresses.

It is correct that you don't see them in the routing table: as explained in a previous thread actually it is a single IPv6 /64 subnet using eui-64 format what you get.

Link local are very important in IPv6:

all mechanisms of Neighbor discovery, stateless address configuration (to learn unicast aggregatable addresses, link local or the modern unique local RFC4193), duplicate address detection,

ipv6 IGP adjacencies use link local.

Link local are used as source or destination addresses for all these activities.

Without link local what could be a valid ipv6 address to send a Router Solicitation for a just powered up ipv6 host ?

A RS uses FF02::2 (all routers in subnet) destination and uses the link local address as source (after the check for address duplication is passed the link local can be used).

In some ways link locals are a known starting point to allow all the activities on the link without using any broadcast or the old ARP protocol:

because an ipv6 host can have multiple ipv6 addresses on a NIC, link local are there to allow a start.

There is no ipv4 equivalent of this because ipv4 doesn't support multiple ip addresses per interface (yes there are secondary ip addresses but it is not the same).

Hope to help

Giuseppe