On 15/09/2023 1:38 am, Wietse Venema via Postfix-users wrote:
Marc Lucke via Postfix-users:
On 15/09/2023 12:08 am, Wietse Venema via Postfix-users wrote:
Marc Lucke via Postfix-users:
re:
https://techcommunity.microsoft.com/t5/exchange-team-blog/updated-requirements-for-smtp-relay-through-exchange-online/ba-p/3851357
That text is about relaying email: you originate a message, and use
Postfix to ask a Microsoft email service to deliver that message
to some recipient on the Internet.
As documented at the link that you cite, Microsoft requires that
the SMTP client is authorized to use the MAIL FROM domain.
Let's say I send an email. I use:
> mail from: <annoy...@spammer.com>
and in the data (body)
> From: Professional Legit Person
<igotalovelybunchofcoconuts@innocent.pizza>
That appears to be a different use case: you are not originating a
message for some recipient on the Internet, instead you appear to
be using Postfix to forward a message from the Internet to a Microsoft
email service.
For this, your best bet is to forward the message as an attachment,
instead of inline. That is, create a new email message, from your
email address, and attach the forwarded message as message/rfc822.
I do this sporadically, using the 'forward' feature of a mail reader
program. If you want to do this in some automated manner, perhaps
Bill Cole has some tooling suggestions.
Wietse
Thanks Wietse. Not my use case. It's a simple store & forward MTA &
the senders will always be local & authorized - that's already taken
care of.
You need to prove that to a remote SMTP server (e.g., Microsoft)
with DMARC, DKIM, SPF, and so on.
I literally would like to know how to make it so that whatever
the "mail from: " that was used is none of Microsoft's, or anyone
else's, business, & if that's possible. But I'm also annoyed that I
have to.
You would have to invent time traval and go back 20 years, when
email receivers were more liberal in what MAIL FROM address they
accepted.
Wietse
ah - the good 'ol days when I was a kid running an ISP (the tech
stuff). Kind of makes me nostalgic for sendmail. dmarc, dkim, spf -
yes, I get it - I was wondering if someone would pick up on that. All
email flowing through my postfix is legitimate and valid as if it was a
client, just a huge job with a risk of missing important instances to
identify where P1 != P2 (as Microsloth call it). At least (I think),
I'm not missing any obvious config option :) Thanks anyhow.
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