IPv6 words

Joel Jaeggli joelja at bogus.com
Fri Jun 24 10:16:38 CDT 2011


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 at ufp.org - CCIE 3440
>        PGP keys at http://www.ufp.org/~bicknell/





More information about the NANOG mailing list