IPv6 Link Local Addresses

[Doug Hardie]

With FreeBSD 9.1-RC2 you can assign the same link local address manually to two different hosts on the same network.  The Neighbor Solicitations are not responded to and you end up with non-working addresses.  The simple way to reproduce this is to boot two systems on the same network and get the link local for system 1.  Shut it off and manually assign that address to system 2.  Then boot system 1.  System 1 will send the Neighbor Solicitation but system 2 will not respond to show that address is in use so system 1 uses the duplicate address.

Even more interesting, I have another system, 9.1-RC2, that when it comes up never sends the Neighbor Solication.  It just starts using the link local address.  I can't find any significant differences between those two systems other that the first was a direct install from the CD and the second was a freebsd-update from 9.1-RC1.

Should I send a PR or is this a known issue?