why IPv6 isn't ready for prime time, SMTP edition

Brielle Bruns bruns at 2mbit.com
Wed Mar 26 01:24:58 UTC 2014

On 3/25/14, 5:35 PM, John Levine wrote:
> In article<3D7D0845-CB25-4C05-8FAB-F5728C8602DD at heliacal.net>  you write:
>> >The OP doesn't have control over the reverse DNS on the AT&T 6rd.
> Ah, OK, you're saying that their IPv6 isn't ready for prime time.
>> >One would hope that with IPv6 this would change, but the attitude of looking down on end subscribers has been around
>> >forever.
> It has nothing to do with looking down on "subscribers" and everything
> to do with practicality.  When 99,9% of mail sent directly from
> consumer IP ranges is botnet spam, and I think that's a reasonable
> estimate, we have better things to do than to spend a lot of our money
> expensively filtering that spam for the benefit of the GWL who is too
> cool to relay through a mail server with a real name.

I'm sure you are as vocal about outright rejecting messages for lack of 
SPF (even if softfail) and lack of DKIM as you are about requiring rDNS?

Or perhaps making TLS mandatory, outright rejecting cleartext.

Seems like the logical next step...    Maybe too much overkill though, 
right? Hard to define when you cross over that line.

Last time I checked, there is no RFC that states that using SMTP 
transport is mandatory with the originator having rDNS (ipv4/ipv6).  It 
an arbitrary decision made by each mail provider.

Obviously, Google will do whatever they want, which is within their 
right.  Doesn't mean though, that I can't express my disgust/annoyance 
in them doing it and for the added hassle it causes me.


I hope you understand where I'm coming from, John.  I'm a huge supporter 
of IPv6 deployment - and have been using every opportunity I have had at 
my disposal to bring it to my end users, and make them excited about it too.

The problem is, it blows my cred and rep with my end users when on day 
one of getting them set up and fully running on IPv6, they can't e-mail 
the local school district, or their business partners, because the other 
end uses Google mail.  It makes me look like an idiot, and they start 
questioning why should they waste time/money on getting to be IPv6 ready.

These kind of issues are things we are trying to avoid, but seem to be 
shooting ourselves in the foot on, even if unintentionally.  Everything 
is a tradeoff, and in this case, I don't believe the tradeoff is worth 
the hassle it can cause.

Brielle Bruns
The Summit Open Source Development Group
http://www.sosdg.org    /     http://www.ahbl.org

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