[TwoNineFive]

I run my own mail servers and hotmail and other Microsoft-based email services regularly blocks my mail by source IP on the various domains I run.

I've been using the same /29 network for over 15 years now. There's no nearby adjacent networks that are on any blacklists.

I monitor blacklists on a regular basis.

No marketing. The domains I run are strictly personal and projects. I monitor volume and all kinds of stuff. I know there's nothing like spam or any kind of marketing going outbound.

It's astonishing how honest Microsoft is when I send them an email telling them to unblock. They literally just admit that they never had reason to block the domain/IP and they unlist it for a few years and then it goes back on their list.

It's become apparent that they blacklist by default.

Fortunately I only run into the occasional idiot who uses Hotmail or live.com.