Ariel Costas

Dealing with Outlook (again)

By Ariel Costas - October 30, 2021

I think this will be the last post regarding the Microsoft email topic, after my article “Microsoft’s control over email”1 two weeks ago. I’ve found a workaround that doesn’t involve relaying all of my email over Amazon’s SES service or any similar.

Postfix has some configurations called “transport_maps”, that allow you to redirect email to certain domains through a relay, and only those. So I signed up for a SMTP relay service, configured DKIM and all that crap to allow it, and told Postfix to send email to @(outlook|msn|hotmail|live) to use that transport. I also added some extra domains that needed to be proxied (because they are hosted on Micro$oft 365).

I didn’t want the problem to end like this, but I guess there’s no more options, as Microsoft closed a ticket opened by me refusing to unban my IP for “not complying with their requirements”. So this is it. Microsoft, fuck you, once again.


  1. https://costas.dev/microsofts-control-over-email/ ↩︎