Domain publishes a null MX (receives no mail)
Updated
What this check looks for
Your domain explicitly declares that it does not accept email. That is a valid and useful configuration for a domain that only hosts a website.
Why it matters
A null MX makes rejection immediate and explicit rather than leaving senders to time out, and it discourages the domain being used as a forged return address.
What it costs your score
This check never deducts. It reports a fact — or reports that something could not be verified — and is shown on the report without moving the score.
- Severity
- info
- Default confidence
- confirmed
- Status when triggered
- info
- Deduction
- 0 points
- Family cap
- none
- Category
- Email transport
- Module
- Email mx
- Fix owned by
- dns host
- In the ruleset since
- 2026.09
How to fix it
Nothing to do, unless you intended this domain to receive mail.
A null MX is the correct configuration for a domain that does not handle email.
If the domain should receive mail, replace the null MX with your provider's MX records.
Consider also publishing
v=spf1 -alland a DMARC record atp=rejectso the domain cannot be forged.
How to confirm it worked
dig +short MX ‹domain› — expect '0 .' for a null MX
A named slot like ‹domain› — and the braces left in the configuration below — is filled in with your own values when this rule appears on a report.
Technical detail
‹domain› publishes a single MX record with preference 0 and a target of ., the null MX of RFC 7505. Senders reject the message at submission time with a 5xx. Because no mail is sent from this domain either, the email authentication checks below are reported as not applicable rather than as failures.
Standards and references
Test this on your domain
Run the check that produces this finding, on its own, against any domain.