> Cloudflare can't 'properly' MITM the inbound email.
Define 'properly'.
It's a bog-standard forwarding specifically because this is the only way to have to separate systems to operate.
Gmail doesn't know what `yourdomain.tld`[0] is yours and what if it receives anyhting to *@yourdomain.tld it should route it to [email protected].
If you don't point yourdomain.tld MX records to Cloudflare then Cloudflare would never receive anything to @yourdomain.tld, because MX doesn't point at them.
[0] the only way to for it know that is to run some Google Business or whatever it called now, where you actually ... point yourdomain.tld MX records to Gmail and it would process them... but it would not deliver them to [email protected]!
BTW it would be absolutely the same idea if instead of Cloudflare you would use Google Business (again, whatsitsname). You would setup 'Send As' in [email protected] as a usual SMTP identity which would allow you to use Gmail interface to send from [email protected], and similar you need some way to explain to Google/Gmail what all mails at *@yourdomain.tld should be forwarded to [email protected].
Define 'properly'.
It's a bog-standard forwarding specifically because this is the only way to have to separate systems to operate.
Gmail doesn't know what `yourdomain.tld`[0] is yours and what if it receives anyhting to *@yourdomain.tld it should route it to [email protected].
If you don't point yourdomain.tld MX records to Cloudflare then Cloudflare would never receive anything to @yourdomain.tld, because MX doesn't point at them.
[0] the only way to for it know that is to run some Google Business or whatever it called now, where you actually ... point yourdomain.tld MX records to Gmail and it would process them... but it would not deliver them to [email protected]!
BTW it would be absolutely the same idea if instead of Cloudflare you would use Google Business (again, whatsitsname). You would setup 'Send As' in [email protected] as a usual SMTP identity which would allow you to use Gmail interface to send from [email protected], and similar you need some way to explain to Google/Gmail what all mails at *@yourdomain.tld should be forwarded to [email protected].