Email receiver test

Test how your domain receives mail — the way a real sending server experiences it. The domain security check reads your DNS records; this test makes an actual SMTP connection to your MX and checks delivery on the wire: is a mail exchanger reachable, does it offer STARTTLS, is the recipient accepted at RCPT, does it accept any address (catch-all), does it accept postmaster@, is greylisting active? The catch-all, postmaster and open-relay checks stop at RCPT (no message body); then one signed proof message is delivered through the full DATA stage to exactly the address you proved you control — and nowhere else — to confirm that real mail arrives end-to-end.

You prove control first. To make sure we only ever probe a domain that belongs to you, we ask you to send us one email from the domain you want to test. That email is authenticated (SPF against the real connecting IP, or an aligned DKIM signature); we then run the delivery test against exactly the address you sent from — never an address you type in. No signup, no tracking; the proof address is single-use and expires, and the report lives only in memory for a short while.