How to wish you hadn't forced ipv6 adoption (was "How to force rapid ipv6 adoption")

Philip Dorr tagno25 at
Fri Oct 2 04:14:35 UTC 2015

On Thu, Oct 1, 2015 at 10:58 PM, Rob McEwen <rob at> wrote:
> On 10/1/2015 11:44 PM, Mark Andrews wrote:
>> IPv6 really isn't much different to IPv4.  You use sites /48's
>> rather than addresses /32's (which are effectively sites).  ISP's
>> still need to justify their address space allocations to RIR's so
>> their isn't infinite numbers of sites that a spammer can get.
> A /48 can be subdivided into 65K subnets. That is 65 *THOUSAND*... not the
> 256 IPs that one gets with an IPv4 /24 block. So if a somewhat legit hoster
> assigns various /64s to DIFFERENT customers of theirs... that is a lot of
> collateral damage that would be caused by listing at the /48 level, should
> just one customer be a bad-apple spammer, or just one legit customer have a
> compromised system one day.

As a provider (ISP or Hosting), you should hand the customers at a
minimum a /56, if not a /48.  The provider should have at a minimum a
/32.  If the provider is only giving their customers a /64, then they
deserve all the pain they receive.

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