[Mailman-Users] Mailman Hosting

Richard Shetron guest2 at sgeinc.com
Fri Dec 23 09:36:17 EST 2016

Maybe they were using some type of grey listing.

For those who don't know:
Grey listing is where the target MTA rejects with a retry error code the 
email from a new source for some period of time.  Every site can set 
their own delay.  Most spammers won't retry so it gets rid of a lot of 
spam.  Real email servers will accept the retry error (4xx) and retry 
after some prefigured time from a few seconds to an hour or more.  The 
IP addresses are tracked and if retried after the time limit are white 
listed for anywhere from a few hours to a month or more.

On 12/23/2016 1:40 AM, Mark Dale wrote:
> Thanks for the suggestion on the mailop list Jim.
> Verizon began accepting mail again for lists on the European server
> about 6 hours ago.
> No light was shed as to why or what changed their view. Not only Verizon
> but AT&T as well, at around the same time - a little puzzle that's
> probably best left alone.
> It may be that their default position is to block all list mail
> regardless - until they get swamped with complaints.
> I've subscribed to the mailop list as you suggest, and if I learn
> anything relevant to this issue I'll post it back here.
> Thanks,
> Mark
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> On 22/12/16 16:15, Jim Popovitch wrote:
>> On Wed, Dec 21, 2016 at 11:42 PM, Mark Dale <mark at mailmanlists.net>
>> wrote:
> ...
>>> All the DNS records (inc SPF, DKIM) are in place, the server is on no
>>> RBLs,
>>> con-current connections to the recieving mail servers is set at 2 in
>>> Postfix. In short, all the right boxes are ticked as far as we can see.
>>> Point noted about the time needed to build a good IP reputation. In
>>> light of
>>> that, we moved the list to our old established server in Europe. It
>>> has a
>>> SenderScore of 99, and of course all the same boxes are ticked. Verizon
>>> still rejected list mail.
> ...
>> A good place to start is on the mailop list, explain your company and
>> sign-up practices/filtering, etc.  Be open and ask for specific reps
>> to contact you offline if necessary.  You may get some awesome help,
>> although this close to the holidays your message may not hit the right
>> people until next year.
>> https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop
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