It's Ars Tech's turn to bang the IPv4 exhaustion drum

Michael Thomas mike at
Tue Aug 19 12:25:49 CDT 2008

Justin M. Streiner wrote:
> On Tue, 19 Aug 2008, michael.dillon at wrote:
>>> I don't have a problem with assigning customers a /64 of v6
>>> space.
>> Why so little? Normally customers get a /48 except for residential
>> customers who can be given a /56 if you want to keep track of
>> different block sizes. If ARIN will give you a /48 for every
>> customer, then why be miserly with addresses?
> I don't operate an ISP network (not anymore, anyway...).  My customers 
> are departments within my organization, so a /64 per department/VLAN is 
> more sane/reasonable for my environment.

Uh, the lower 64 bits of an IP6 address aren't used for routing you
know? They're essentially the mac address, or some other sort of
autoconf'd host identifier. Last I heard, the smallest allocation is
supposed to be a /48 -- I hadn't heard of the /56 thing that Michael
was speaking of, though I'm not surprised. There's 64 bits for
routing... no need to be so stingy :)


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