What are MX records?

MX (Mail Exchanger) records are the DNS records that say where email for your domain should be delivered. When someone sends a message to anyone@example.com, their mail server looks up the MX records for example.com and connects to the listed server. No MX record usually means no inbound email, although receivers will fall back to the domain’s A record.

Priority and redundancy

Each MX record has a priority number; lower is tried first. Providers that run several inbound servers publish several records so mail is retried elsewhere if one is down. Google Workspace now uses a single record (smtp.google.com) that fronts its own redundant infrastructure, so one record is not automatically a problem.

Example record
Name
example.com
Type
MX
Value
10 smtp.google.com.

Null MX: saying "this domain does not accept email"

A domain that never receives mail (a parked or brand domain) should publish a null MX: a single record with priority 0 and the target "." (RFC 7505). Senders then fail immediately instead of retrying for days, and combined with v=spf1 -all and DMARC p=reject the domain cannot be used for spoofing either.

Example record
Name
example.net
Type
MX
Value
0 .

Common MX mistakes

  • Pointing MX at a CNAME or an IP address; MX targets must be hostnames with A/AAAA records.
  • Leaving the old provider’s records in place after migrating, so some mail goes to a dead server.
  • Publishing no MX for a domain that people email, relying on the A record fallback.
  • Not publishing a null MX for domains that should never receive mail.

Frequently asked questions

Do I need more than one MX record?
Not necessarily. Large providers publish redundancy behind a single hostname. Multiple records help when you run your own servers or want a backup relay.
What is a null MX record?
An MX record with priority 0 and target "." that declares the domain does not accept email. Use it on parked domains alongside v=spf1 -all and DMARC p=reject.
Can MX records point to an IP address?
No. They must point to a hostname that has an A or AAAA record.

Check your own domain. The scan shows your live records, a score out of 100 and the exact record to publish for each fix.

Related guides

Canonical: https://astraverify.com/what-are-mx-records