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List:       postfix-users
Subject:    Re: Google rejecting IPv6 mails
From:       /dev/rob0 <rob0 () gmx ! co ! uk>
Date:       2013-10-13 20:00:47
Message-ID: 20131013200047.GP9230 () harrier ! slackbuilds ! org
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On Sun, Oct 13, 2013 at 09:26:12PM +0200, Dominik George wrote:
> > There is, in fact, no reliable lsit of *all* mail hosts that will 
> > ever (as in, for a long time in the future) be the sending MTAs 
> > of Google-hosted domains.
> 
> Apart from that, I am tired of implementing exceptions for each and 
> every big proprietary mail provider out there. If a company desires 
> to take part in federated e-mail communicaiton, I expect them to 
> set up there stuff the way others expect it. If there setup is too 
> huge to manage it without awkward tricks, like Google dynamically 
> assigning roles to servers and not even reliably using subnets, 
> whatever, for certain roles, then they are by definition not up to 
> the task of operating it, be it for conceptional or personnel 
> limitations. If we go ahead and teach all _other_ mail systems to 
> fit their needs, we effectively do the work their customers pay 
> them for.
> 
> I am close to deciding not to opt-in to that and simply not 
> accepting their mail if I can't using standard configurations.

Amen. Along those lines, Postfix 2.11 will be the most important 
minor version since the introduction of postscreen itself in 2.8. At 
last we can have the benefits of postscreen zombie detection without 
the pain of greylisting.

Gmail and just about every big proprietary mail provider out there 
maintains lists of their hosts on dnswl.org. Postscreen with a 
relatively simple DNSBL configuration, including a negative point 
lookup for list.dnswl.org, will make this all very easy and low 
maintenance. (Consider signing up for dnswl.org yourself; it costs 
only a few minutes of your time.)

http://www.postfix.org/postconf.5.html#postscreen_dnsbl_whitelist_threshold
http://dnswl.org/

My postscreen page, not yet updated for 2.11:
http://rob0.nodns4.us/postscreen.html
-- 
  http://rob0.nodns4.us/ -- system administration and consulting
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