Rate of growth on IPv6 not fast enough?

Matthew Kaufman matthew at matthew.at
Fri Apr 23 00:18:56 CDT 2010

Owen DeLong wrote:
> On Apr 22, 2010, at 5:55 AM, Jim Burwell wrote:
>> Hash: SHA1
>> On 4/22/2010 05:34, Simon Perreault wrote:
>>> On 2010-04-22 07:18, William Herrin wrote:
>>>> On the other hand, I could swear I've seen a draft where the PC
>>>> picks up random unused addresses in the lower 64 for each new
>>>> outbound connection for anonymity purposes.
>>> That's probably RFC 4941. It's available in pretty much all
>>> operating systems. I don't think there's any IPR issue to be afraid
>>> of.
>>> Simon
>> I think this is different.  They're talking about using a new IPv6 for
>> each connection.  RFC4941 just changes it over time IIRC.  IMHO that's
>> still pretty good privacy, at least on par with a NATed IPv4 from the
>> outside perspective, especially if you rotated through temporary IPv6s
>> fairly frequently.
> 4941 specified changing over time as one possibility.  It does allow
> for per flow or any other host based determination of when it needs a new
> address.
> Owen
But none of this does what NAT does for a big enterprise, which is to 
*hide internal topology*. Yes, addressing the privacy concerns that come 
from using lower-64-bits-derived-from-MAC-address is required, but it is 
also necessary (for some organizations) to make it impossible to tell 
that this host is on the same subnet as that other host, as that would 
expose information like which host you might want to attack in order to 
get access to the financial or medical records, as well as whether or 
not the executive floor is where these interesting website hits came from.

Matthew Kaufman

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