[jeffbee]

Judging from my own spam label on gmail, those messages are part of the torrent of junk that is pouring out of Microsoft's "hybrid on-premises exchange" egress VIPs. Basically some clown who pays Microsoft for quasi-hosted Exchange has a virus that sends spam, and Microsoft blesses it with the reputation of the customer egress addresses. Eventually, this will stop working for Microsoft but at this time it's like waiting for Greenland to melt: inevitable, but takes a long time.

Also worth noting if you are trying to evaluate gmail's classification performance that the vast majority of what they think was spam is not in your spam label, it got stopped with a 4xx error code at SMTP time. So you don't really have a way to know the denominator.

[jamespo]

Ironically Microsoft are the only major MX that won't accept email from my server.

[tracker1]

And good luck getting off that list if you're on a hosted VPS... they're about impossible... I can get through to hotmail and o365, but not the outlook.com block. (shrug)

I'm relaying through SendGrid as I just don't have that many emails coming from/through my server that it's worth the lowest paid level (there is a free tier) to have to worry about it...

I've been considering setting up a higher end server (compared to the $20/mo vps I'd been using) at a data center and seeing what I can manage as a direct mail host without the relay. But 10x-ing my costs just doesn't feel right for something that will take more time and not generate revenue that I'm not that passionate about.

For those curious, been looking at WildDuck mail which seems like an interesting structure and the features are cool, just not sure I want to go through it all. I've been using Mailu via docker-compose on DigitalOcean for a couple years for all my lesser used domains/addresses, relaying through SendGrid. It works but kind of annoying going through setting up each domain added through the relay.

[progval]

My dedicated server is also blocked by MS. https://sendersupport.olc.protection.outlook.com/snds/ is supposed to help me resolve it, but it says my IP address has no reported incident.

Ironically, SendGrid is the main source of spam passing through my spam filters; but I can't block it because about 1/4th of emails I get from them are not spam

[eightysixfour]

Funny. I'm on Outlook and mine is (sort of) the opposite, most of the spam that comes through is @gmail.com these days. Seems like spammers are taking advantage of known trusted relationships between services to increase delivery rates to specific domains.