The rumor is that domainepublic.net treats Microsoft’s mail server with the same reciprocity of Microsoft’s treatment of other mail servers and thus blocks MS.
IIRC, small email services are forced to solve a CAPTCHA to prove to MS that their server has a human administrator before the server can connect to MS’s server. Is that true?
Can anyone confirm or deny the rumor as well as whether MS forces other ESPs to solve CAPTCHAs? I would be quite interested in having an email account that blocks MS until an MS admin solves a CAPTCHA (which I assume would not happen).
Most legit providers offer filter rules you can configure as you need. Particularly if you’re using a paid enterprise service. You could check to see what rules a provider has available and if you can block by MX record or IP. You wouldn’t need to control the server, just have a provider that let’s you customize your needs.
Unless you are intentionally finding services that do not use M$ infrastructure then you risk losing a lot of access. Flights, trains, hospitals, schools, stores, events may all use M$ as a provider whether or not they are sending from their own domain. Personally I’d rather receive my tickets that I pay for than not.
Filters are for email post-delivery. By the time a server is executing your filter instructions, Microsoft’s server has already delivered the message and disconnected. It’s too late at that point. If some rare mail service were to bounce a message based on user-specified filters, it would have to be after the msg has already been delivered. This would risk “backscatter”, whereby the bounced response attempts to connect to the /perceived/ sending server, which could be incorrect. And even if it is correct, the sending server may not accept the bounced msg.
The configuration I describe can only competently be done on the server and it necessarily must be the same behavior for all users on that server because the refusal happens before the sending server even has a chance to send an SMTP “RCPT TO” line.
It would be senders who lose access. I’m already happy to not connect to surveillance advertisers. The idea is that users on surveillance ad platforms lose access so they cannot deliver to my inbox.