On 11 Jul 2019, at 14:55, Daniel Stirnimann <daniel.stirnimann@switch.ch> wrote:

The pointers have been given before. This is your problem:

https://www.spamhaus.org/query/ip/79.134.251.203

Daniel


Yes above is my problem but at the same time it can not be the reason for mail delivery to bluewin.ch coming back with a cryptic  DNSNULL error

Spamhaus has a issue with a customer of mine but they have not shown any proof. Above IP however is not in the disputed IP range, its my my well maintained mailserver which has never sent any spam and is not listed as sending any spam anywhere else. What Spamhaus is doing is trying to get ISPs to cancel contracts with well paying customers on first call (no judge, no proof) by putting the ISP's whole IP range into a blacklist (a /19 !) and thus punishing legitimate 3rd parties as well. This is called coercion (Nötigung) which is a criminal offense punishable by law for up to 3 years in jail. We will see if Spamhaus prefers to go to jal or change their blacklisting policy.

Never the less. Sending emailst o bluewin.ch has never been affected. I sent emails successfuly yesterday to bluewin users without a problem. I don't think Spamhaus's blacklist are being used by bluewin.ch as otherwise we would have had issues a lot earlier.

So this doesn't explain any DNSNULL error. And frankly, the error message is really stupid misleading...



On 11.07.19 14:25, Andreas Fink wrote:
Except that this is not applicable. In my case my mailserver is not
hosted at Swisscom but on my own infrastructure, is on the same IP since
years, has proper MX records and reverse DNS entries and has delivered
email to the same bluewin customer yesterday successfully. Only the
reply on that receiver today which I received and replied again got
rejected. And the response is cryptic to me.  

And if you mail to abuse@bluewin.ch <mailto:abuse@bluewin.ch> you get
the same error...

So who is this famous DNSNULL I should contact?



On 11 Jul 2019, at 13:49, Florin sfetea <f_sfetea@yahoo.com
<mailto:f_sfetea@yahoo.com>> wrote:

See https://community.swisscom.ch/t5/E-Mail/Bluewin-akzeptiert-E-Mails-von-eigener-Domain-nicht/td-p/570002
 
 
Beste Grüsse, Regards si s-auzim de bine 
Florin Sfetea
 
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Today's Topics:
 
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----------------------------------------------------------------------
 
Message: 1
Date: Thu, 11 Jul 2019 11:32:38 +0200
From: Andreas Fink <afink@list.fink.org <mailto:afink@list.fink.org>>
To: "swinog@swinog.ch <mailto:swinog@swinog.ch>" <swinog@swinog.ch
<mailto:swinog@swinog.ch>>
Subject: [swinog] bluewin & DNSNULL
Message-ID: <75DA5D85-1A68-4D10-94B8-6237FD9D54DB@list.fink.org
<mailto:75DA5D85-1A68-4D10-94B8-6237FD9D54DB@list.fink.org>>
Content-Type: text/plain; charset="us-ascii"
 
 
Does any one have a clue what DNSNULL means in the following context
of a mail delivery error?
 
 
 
<....@bluewin.ch
<http://bluewin.ch/> <mailto:claudine.beaud@bluewin.ch>>
(mx-v02.bluewin.ch
<http://mx-v02.bluewin.ch/> <http://mx-v02.bluewin.ch/>:
554 mxbw.lb.bluewin.ch
<http://mxbw.lb.bluewin.ch/><http://mxbw.lb.bluewin.ch/> vim
dzmsp-mxin12.bluewin.ch
<http://dzmsp-mxin12.bluewin.ch/> <http://dzmsp-mxin12.bluewin.ch/>
Swisscom AG IP: 79.134.251.203, You are not allowed 
to send us mail. Please see DNSNULL if you feel this is in
error)Reporting-MTA: dns; mail.fink.org
<http://mail.fink.org/> <http://mail.fink.org/>
Arrival-Date: Thu, 11 Jul 2019 11:19:58 +0200
...