Re: [Asrg] How will we manage IPv6 spam?

[Daniel Feenberg <[e-mail]>]

On Fri, 17 Aug 2012, Michael Thomas wrote:

> On 08/17/2012 01:51 PM, Daniel Feenberg wrote:
>> 
>> 
>> On Fri, 17 Aug 2012, John R. Levine wrote:
>> 
>>> Hi.  Remember the ASRG?  I was hoping it might do a little research.
>>> 
>>> In talking to people about IPv6 mail, I'm still coming to the conclusion 
>>> that anyone who thinks they know how they're going to handle it, beyond 
>>> the current toy scale, doesn't understand the problem.  Things we might 
>>> address include:
>>> 
>> 
>> I would not expect to accept any IPv6 mail until users come forward to show 
>> me that they wish to correspond with MTAs that have no IPv4 connection 
>> ability. While this may happen in the fullness of time, I don't expect it 
>> soon. Now and for the foreseeable future such a system would have very 
>> little connectivity, far less than a blacklisted spam source.
>
> Host operating systems -- all of them to my knowledge -- prefer v6 over 
> v4 if you have a public v6 address. So the mere existence of a AAAA 
> associated with the MX will cause the sender to pick the v6 destination. 
> I have a v6 mail system and got bitten because I had forgot to put up 
> the v6 reverse map. It will happen just as a natural consequence of 
> people enabling v6 on their infrastructure.

This sounds inconvenient. If I want to accept mail from one IPv6 host, 
then all the IPv6 hosts will want to use IPv6, and unless I accept mail 
from unknown IPv6 hosts, mail from hosts that would have been accepted 
over IPv4 will be rejected? That is a problem, but I can't imagine IPv6 
acceptance being so universal that there would be more desirable mail from 
IPv6 only hosts than from IPv4 only hosts, at least not for some decades. 
This is especially true since more important hosts are more likely to have 
access to IPv4 addresses. I actually wonder if the transition could ever 
occur as long as IPv4 is supported at all by ISPs.

daniel feenberg
NBER

>
> Mike
>