An MX record, short for mail exchange record, tells the rest of the internet which servers receive email for a domain. Without one, other mail servers do not know where to deliver messages sent to your addresses.
How MX Records Work
Each MX record has two parts: a priority number and the name of a mail server. When someone sends you an email, their server looks up your MX records and tries the server with the lowest number first. If that server does not answer, it tries the next one. A domain can have one MX record or several.
Priority Numbers Explained
Lower numbers mean higher priority. A record with priority 10 is tried before one with priority 20. Records with the same number share the load. Large providers often list several servers with different priorities, so mail still arrives if one server is down.
Common MX Mistakes
An MX record must point to a name, not directly to an IP address, and that name must have its own address record. It should not point to a CNAME alias. Another common problem comes after switching email providers: old MX records left in place send some mail to the old service, so messages seem to go missing at random. When you move email, replace the MX records completely with the new provider’s values.
The Domibot MX Record Lookup shows where a domain’s email goes, which provider runs it and whether each server is answering.