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MX Health Checker

Check the health of your mail exchange servers. Tests IP resolution, PTR match, SMTP port 25 reachability, and STARTTLS capability for each MX record.

Examples:

Enter a domain to check MX records and mail server health

Related Tools

SMTP Test

Check if a mail server accepts connections on ports 25, 465, and 587. Also tests STARTTLS and TLS security for all MX servers.

Email Security

Check MTA-STS transport security policy and BIMI brand indicator record for any domain - both in one lookup.

Email Inspector

Enter an email address to validate it and grade its domain security, or enter a domain alone to check SPF, DMARC, DKIM, and MX records.

About this tool

Each mail exchange server handling email for a domain should have a valid A record, a matching PTR (reverse DNS) record, and SMTP port 25 open to receive mail. A PTR mismatch is a common cause of deliverability issues since many receiving servers perform forward-confirmed reverse DNS (FCrDNS) checks.

STARTTLS on port 25 enables opportunistic TLS encryption for server-to-server email delivery. Without it, all inbound and outbound mail is transmitted in plaintext. For enforced TLS, pair STARTTLS with an MTA-STS policy and the SMTP TLS Checker.