I run my own MTA for some 23+ years now. Google (supposedly) reads only my emails sent by their users and same can be said about other similar services.<p>> The Simple Mail Transfer Protocol (SMTP) relies on MX records in the DNS to identify which server(s) it should hand the mail off to.<p>Not necessarily (this statement is corrected later in the post). One of my domains have no MX records and I use it for email extensively. As per RFC2821, SMTP falls back to A (and AAAA which have not existed back then) when the FQDN does not have corresponding MX record [1]. I have only found it to be an issue with one web service which utilizes hunter.io, which marks my email address as invalid due to lack of an MX record. Real mail services work perfectly fine. They (hunter.io) have the following untruthful statement in their FAQ [2]:<p>>> We check if there are MX records on the domain. If there aren't, the email address can't receive emails.<p>Linked post reflects lack of requirement for the MX record correctly:<p>> As it turns out, no explicit MX record is indeed the most widely found configuration: almost 119 million domains (58% of all domains) are lacking any such resource record. Of those, 76 million (64%) do have an IP address and thus could at least theoretically receive mail<p>[1] <a href="https://www.rfc-editor.org/rfc/rfc2821#section-3.6" rel="nofollow">https://www.rfc-editor.org/rfc/rfc2821#section-3.6</a><p>[2] <a href="https://hunter.io/email-verifier" rel="nofollow">https://hunter.io/email-verifier</a>
> everymailbox.com domain has 398 MX records<p>Ah yeah, these clowns. I distinctly recall, when rewriting the DNS record cache used internally at Google (note: not the resolver), thinking that surely no MX response would need more than 8KiB, and finding these jokers.
It would be interesting to evaluate whether my nameserver provider (Cloudflare) or my mail provider (Fastmail) are sharing access to my emails with anyone else. I chose these providers because I don't want Google reading my emails. I assume that because it's a cleartext protocol and Fastmail operates in Australia that all of my emails are accessible in theory to state actors.
An article from long ago about this problem:<p><a href="https://mako.cc/copyrighteous/google-has-most-of-my-email-because-it-has-all-of-yours" rel="nofollow">https://mako.cc/copyrighteous/google-has-most-of-my-email-be...</a>
Superb analysis. TL;DR:<p>> pretty much boils down to "Google and Microsoft". Even if your domain doesn't use one of their mail servers, chances are that whoever you are sending mail to does.
I was speaking about Paypay in a gMail exchange yesterday and today saw an add about Paypay on my Smart TV (YouTube App). Weird coincidence. The first time ever that I have seen a Paypay ad on Youtube.