Safe Open Relay Check
Safely check whether domain MX servers accept an external controlled recipient.
What this test checks
Up to three public MX hosts: DNS resolution, TCP/25, EHLO, controlled MAIL FROM and RCPT TO, then RSET and QUIT. No DATA is sent.
Why this matters
An MX that accepts an external controlled recipient at RCPT can warrant administrator investigation, but RCPT acceptance alone is not delivery proof.
How to fix common problems
Investigate possible behavior with the mail administrator. Keep relay controls restricted; this tool reports a signal, not a confirmed open relay.
FAQ
Does this send an email?
No. It never sends SMTP DATA or a message body.
Can I select a mail server or recipient?
No. The domain MX records and DomainPulse-controlled identities are the only targets and identities used.