Private use of non-RFC1918 IP space (IPv6-MW)

Seth Mattinen sethm at
Thu Feb 5 02:00:38 UTC 2009

TJ wrote:
>> Some devices will refuse to work if you subnet smaller than a /64. (Yes, poorly designed, etc.)
> Actually, no - not poorly designed.  The spec says it must be a /64 (excluding those starting with 000 binary) so that is what devices (rightfully) expect.  Ref: 

I was just trying to head off the flood of "poorly designed" comments
last time I said such a thing on a different list. ;)

I find /64 convenient because it ends on a nice boundary out of my /48
and for my purposes it's more than enough space. The only annoyance I've
come across was my Cisco devices will only accept an EUI-64 address as a
host address in an ACL. Not a big deal though.


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