DHCPv6 handing out /128 addresses

[GaryElmes]

I've been experimenting with different ways of configuring IPv6 on my router. Yesterday I thought I would take the DHCPv6 service for a spin.

I configured my LAN port with a static /64 address, then configured the DHCPv6 service on that port and configured a "test" device on the local LAN to request it's IPv6 config via DHCP.

The IPv6 address that was sent to the test device by the DHCPv6 service on the router had a /128 subnet mask, instead of the /64 mask I was expecting. Am I missing some configuration step, or is DHCPv6 broken? Surely it's not expected that DHCPv6 will force all local LAN traffic to be tromboned via the router.

(I'm also a bit bemused by the fact that you can't configure DHCPv6 for a port that is tracking a WAN port, but I see that is being discussed elsewhere.)

[Maurice]

DHCPv6 does not work like DHCPv4. DHCPv6 address assignments do not contain prefix or router information. That's why they are considered /128. Clients learn prefixes and routers from Router Advertisements only. If an on-link prefix from RAs matches an address from DHCPv6, local traffic won't go through the router.