What does MX Found mean?

MX stands for Mail Exchange. An MX record is a DNS entry that tells the internet which mail server handles incoming email for a given domain.

MX Found: Yes

The domain has at least one functioning mail server. This is a prerequisite for a valid email address — without MX records, the domain cannot receive email.

MX Found: No

No MX records exist. We then check for an A record (the domain's web server) as a fallback. If neither exists, the email is marked invalid with the reason "no domain records."

MX Found: — (dash)

The MX lookup timed out or returned an ambiguous result. The email is marked unknown with the reason "DNS lookup timed out." This is usually a temporary network issue, not a problem with the email itself.

What we detect from MX records

When we find MX records, we identify the mail provider (Google Workspace, Microsoft 365, Proton Mail, Mimecast, etc.) and apply provider-specific rules. Security gateways like Mimecast and Proofpoint accept all incoming mail at the network edge — catch-all detection on these domains is expected behaviour, not a red flag about the specific email.