What is an MX record? How to read mail-routing results
An MX record identifies a mail exchanger for a domain. It tells a sending system where to attempt email delivery. An MX lookup is therefore a domain-level routing check, not a directory of individual mailboxes.
Open the relevant free tool →An illustrative MX answer
Read the two important fields
A typical result includes a priority number and a mail-server hostname. Lower priority entries are preferred. Multiple records can provide alternative destinations. The hostname is not the recipient address: it identifies receiving infrastructure. A domain can use a third-party mail provider while its website is hosted somewhere else, so the web host is not a reliable guide to the mail setup.
Try a lookup
Enter only the domain, like the part after @, into the MX checker. Review all returned records and their order. If you administer DNS, compare them with the receiving provider’s exact instructions. Do not copy another company’s MX records: provider hostnames can include identifiers specific to that organization.
Distinguish three different outcomes
A list of exchangers means explicit mail routing is published. An empty answer needs more investigation; it is different from a null MX record, which explicitly declares that the domain accepts no mail. A lookup failure can also be temporary. Keep the resolver error if available and retry after resolving the original DNS issue instead of assuming the domain or every contact at it is invalid.
Troubleshoot changes carefully
After moving email providers, check the authoritative configuration and allow for DNS cache lifetimes. Do not delete old records before checking the migration plan. Test both incoming mail and the provider’s account configuration. A correct-looking DNS response cannot create mailboxes, enable a tenant or repair an inactive subscription at the receiving service.
What an MX checker cannot establish
A passing result does not prove that a username exists, that a server will accept your sender, or that a message will land in the inbox. Combine the routing check with address syntax and relevant mailbox evidence. If you are diagnosing an actual bounce, keep the delivery report alongside the lookup. It explains what happened to your message, whereas DNS only describes routing information visible when you checked.
Worked example
Illustrative result: 10 mx1.mail-provider.example; 20 mx2.mail-provider.example. The server with priority 10 is preferred. These example hostnames are not records to publish.