On Jun 24, 2011, at 6:50 AM, Leo Bicknell wrote:
In a message written on Fri, Jun 24, 2011 at 09:10:53AM +0000, Bjoern A. Zeeb wrote:
If you want to do it, make sure you do understand the restrictions that apply to IPv6 addresses, like U/G bits, etc. Too many people unfortunately just think it's cool in a weird geeky sense and violate RFCs with them. I was very close to write an article about that after W6D...
Perhaps I missed something in an RFC somewhere, but I believe those bits only have meaning locally on an Ethernet LAN. They have no meaning when used on non-Ethernet networks, for instance POS or on a Loopback. If someone wanted to use them for a /128 virtual for their web site for instance that would be ok.
Or, turning that around, if you assume an IPv6 address is part of a /64 on an Ethernet network, you have made a false assumption.
A load-balancer attached to it's first hop router via a /126 may well advertise the virtual ip's it's serving (and treat them) as /128s. the assumption that links are /64s falls down a lot (even on ethernet) when most of them are point-to-point.
-- Leo Bicknell - bicknell@ufp.org - CCIE 3440 PGP keys at http://www.ufp.org/~bicknell/