The SMTP protocol isn’t secure and wasn’t designed to be. Email sent in the early days of the Internet were the digital equivalent of sending a postcard through the postal system. Eventually, Transpo...
Updated Apr 22, 2025
Version 5.0
Blog Post
KevinShaughnessy
Microsoft
MicrosoftDeleted great feedback, your O365 DKIM example is a solid one for us to consider. This is the first step, and indeed we'll be looking at building upon it to make it simpler as you suggest. And yep, certificate management is always a challenge for everyone it seems - interesting to consider possible ways we might help with that.
There is no online MTA-STS validator hosted by Microsoft at this time, but I searched "MTA-STS validator" and a few 3rd party options popped up. That said, we just completed the DNSSEC/DANE validator as part of the Microsoft Remote Connectivity Analyzer and I think it makes sense to add a MTA-STS validator to it in the near future. Thanks so much for the feedback, Rafal, great stuff!