MX Health Summary

About Email Health Checking

This tool performs a comprehensive check of a domain's email configuration — looking at MX records, SPF, DMARC, and SMTP port reachability. A healthy email domain has all four components correctly configured to ensure reliable delivery and protection against spoofing and phishing.

The four pillars of email authentication

• MX records — Specify which mail servers accept email for your domain. Without MX records, email cannot be delivered to your domain.
• SPF — Authorises which servers can send email from your domain. Helps prevent spammers from forging your domain as the sender address.
• DKIM — Adds a cryptographic signature to outgoing messages. Proves the email was sent by an authorised server and wasn't modified in transit.
• DMARC — Ties SPF and DKIM together with a policy (none, quarantine, or reject) and provides reporting. Without DMARC, SPF and DKIM provide limited enforcement.

Common email health problems

• No SPF record — Anyone can spoof your domain as the email sender. High spam risk.
• SPF +all — Equivalent to no SPF. The most dangerous SPF configuration.
• DMARC p=none — Provides reports but no enforcement. Spoofed emails still reach inboxes.
• No DMARC — SPF and DKIM checks are done independently with no unified policy or reporting.
• Port 25 closed — Some hosting providers block outbound port 25 to prevent spam. You may need to use a smart host or relay service.