Free MX Lookup

Enter a domain to see its MX records in priority order, the addresses behind each mail server, and who hosts the mailboxes. We flag any record that will stop mail arriving.

Understanding MX records

What MX records look like

Google Workspace publishes a single record:

example.com. MX 1 smtp.google.com.

A primary server with a backup:

example.com. MX 10 mx1.example.com. example.com. MX 20 mx2.example.com.

A domain that should never receive mail can publish a null MX, MX 0 ., so senders give up at once instead of retrying.

What is an MX record?

An MX (mail exchanger) record tells other mail servers where to deliver email for your domain. Each record has a priority and a host name. Senders try the lowest priority number first and fall back to the next one if it is down.

Do MX records affect the email I send?

Not directly. MX records control where mail to your domain arrives. Sending depends on SPF, DKIM and DMARC. But bounces and replies come back through your MX records, and some receivers distrust a sending domain that cannot receive mail at all.

What does MX priority mean?

Lower numbers are tried first. Two records with the same number share the load. A record with a higher number is a backup that senders use only when the first servers do not answer.

Can an MX record point to an IP address or a CNAME?

No. The standard requires a host name that has its own A or AAAA record. Pointing MX at an IP address or at a CNAME breaks delivery with some senders, even if it seems to work with others.

How long do MX changes take?

As long as the TTL on the old records, often an hour or less. During a mailbox migration, lower the TTL a day ahead so the switch happens quickly, then raise it again once mail is flowing.

Receiving is half the picture. Check the sending side with the DMARC checker, which tests SPF, DKIM and DMARC together.

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