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DomainGrade

What we checkEmailEM-08

Mail servers (MX)

MX records say where mail for your domain should be delivered.

Area
Email
Check
EM-08
Included
Free in every scan

What we check

We look up your MX records and read the hosts and priorities.

A single . — the null MX — is a deliberate statement that the domain receives no mail, and we treat it as correct rather than missing.

Why it matters

No MX and no null MX is ambiguous: some senders will fall back to your A record and try to deliver mail to your web server, which is a service that was never meant to receive it.

Getting this wrong is quiet. Mail does not bounce loudly to the person who misconfigured it; it bounces to whoever tried to write to you, and they usually assume the address was wrong rather than the domain.

How to fix it

  1. 1

    If the domain receives mail, publish the MX records your provider specifies.

  2. 2

    If it does not, publish a null MX so senders stop trying.

A null MX, for a domain that receives no mail
yourcompany.com.  IN MX  0 .

Common questions

What is a null MX for?
It says 'this domain accepts no mail' explicitly, so senders fail fast instead of falling back to your web server.
Do MX priorities matter?
Lower numbers are tried first. Backup servers get higher numbers — but a backup that does not know your valid recipients becomes a spam relay, so many providers now recommend a single MX.
My MX points at a hostname that does not resolve.
Then mail to you bounces. That is what EM-09 checks.

See how your domain does on this check.

All 34 checks, a grade, and the exact fix for anything that isn’t right — in about twenty seconds, no signup.

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