On Wed, Sep 21, 2016 at 11:56:14AM +0000, Eric Henson wrote:
Thanks, I was aware of this link however I'm more worried about a problem not
necessarily tied to my own case.
Another user using his own setup also gets spamboxed when mailing me, whereas
someone else using a different MTA doesn't get spamboxed.
I was hoping someone a bit technical could take a look at headers from a mail
I sent myself and tell me "yes there is something wrong, can't tell you what"
or "nope, the problem is not related to your message construct" so that I can
at least know I'm not going to spend time looking in the wrong directions ;-)
Sorry if this is not the right list to ask for similar questions but I know a
bunch of people here could help, trying my chance
> -----Original Message-----
> From: mailop [mailto:mailop-boun...@mailop.org] On Behalf Of Gilles Chehade
> Sent: Wednesday, September 21, 2016 6:02 AM
> To: firstname.lastname@example.org
> Subject: [mailop] anyone from Microsoft around ?
> I'm lead developer of an opensource MTA called OpenSMTPD.
> We run a mailing-list for our project with very low volume, exchanging a few
> thousands messages each month to around 400 people, very few of them being
> hosted at big hosts, all of them having subscribed voluntarily.
> In addition to this, we use a few mailboxes at major hosts and send some
> mails every now and then to ensure we didn't break the smtp engine, this
> usually amounts to less than 10 mails / month per big ISP.
> All of these mails respect all best-practices that we know of:
> - they are sent from long existing domains;
> - they are rate-limited despite low volume;
> - they are DKIM/DomainKeys signed;
> - DNS is properly configured with valid DNS/rDNS for the one IP address;
> - IP address is the same as the MX accepting mail for the domain;
> - SPF is properly declared, so is DMARC;
> I checked senderscore and we actually send so few volume we don't even have a
> reputation visible there.
> I've started receiving complaints about users receiving their messages in the
> spambox only at microsoft-hosted domains. No problem for gmail, yahoo, orange
> and others, just microsoft.
> I did some testing, and it turns out that even the simplest mails will end up
> spamboxed no matter what machine or domain I use to send. The reason
> advertised in the Microsoft appended domains may vary if I turn off DKim,
> strip some or all Received lines, but basically no matter my configuration,
> mails will not be inboxed.
> I'm wondering if there is something wrong in the format of our headers and if
> this could affect users of our software disregarding the kind of mails they
> send with it. I've been tackling this for hours before contacting the mailing
> Any help would be greatly appreciated, I'm running out of ideas :-)
> Gilles Chehade
> https://www.poolp.org @poolpOrg
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