Can Exchange provide list-unsubscribe header functionality?

Question

Here's where I am coming from.
We host our own Exchange, 2016 at present.
We send emails through the week, to members who WANT our emails. (we aren't spamming, marketing, or whatever you want to call it)
Primarily, they are external users, on their own domains or hotmail, gmail, etc.

Recent blocking by Microsoft mail services (hotmail, live, outlook.com) with no NDRs has led us to deeply examine every last way to ensure that the emails get through.
(not sure why it should be this hard, but, apparently it is - MS prefers to "black hole" the emails, not even sending to junk/spam)

Anyhow - one of the items mentioned was, if you're sending to many people, ensure that you have a list-unsubscribe entry in the mail header.
Ok, I'm game, happy to add that.

HOW?

I honestly can't believe after 45 minutes of searching, that there isn't a single posting, on how to add this to Outlook on the outbound side, or, the Exchange server itself, if that's how it must be done.
I mean, it has to be enabled on a particular account, I would assume?
Or be something you can trigger on, when you send an email out?

Surely, if MS is putting so much stock on emails arriving WITH this header, they must support adding it on their own server .... no? :-)

Open to any thoughts, ideas, or direction on even where to look... with my thanks!

Andrew

Answer 1

I'd start with the Authentication checks first.

Do you have SPF/DKIM and DMARC setup? That would probably help if not.

Otherwise Exchange has never been a good high volume "mailing" solution for these types of emails. It just doesnt have the knobs to turn to easily add stuff like this.

Having said that, would a mail flow rule work here and add the header to every message from your sending account.
Might be worth testing out!

Answer 2

ok, so just for Search Fodder... I'll spell it all out. Andy David, thanks for putting me on the right path of where to look. I am not on 365, but a pure exchange server, but the options were there too.

To answer your questions, I've jumped through all of those hoops, a long time ago, and been using https://www.mail-tester.com recently to fully test it all.
Between a Tech support at Hotmail/Outlook/Live sending me a MS Document, that HINTED that they value the List-Unsubscribe header entry, AND the Mail-Tester hitting me for a minor infraction for not having that - I wanted to see it done.
Hope that makes sense.

And... again, I'm not trying to be a marketing guy, or mass-mailer - just trying to reach 100 or so local families on a regular basis, for a charity thing. So, not into fancy campaigns, but have the server at my disposal, so...

In the end, a relatively easy task.
Let's see if I can get a screenshot to paste in here.
From the Exchange Console...

I made a New Rule, and then had to play with what would successfully trigger it.

But, in the end, if I open up any emails I get, that were addressed to ******@1stBinbrook.org that pass through the server, they arrive with the header added. I don't see any difference in gmail, but on my iPhone, there is now that little blue "Unsubscribe" under the subject line, so I know that some devices are picking up the option.

Thanks!

Answer 3

I am being prompted by admins, to accept an answer. :-)
But I think both followup posts need to be flagged as answers, to show a complete picture - can someone here do that? (those are the ones that will pop in the search engines for others)