Check MX Records

Check MX Records for Any Domain

An MX (Mail Exchange) record tells sending mail servers which host accepts email for a domain. When someone emails [email protected], their server looks up the MX records for example.com and connects to the host listed there. Enter a domain above and the tool returns each mail host with its preference value.

Reading the Results

Each line shows a host and a preference number. Senders try the lowest number first. If that server doesn't answer, they move to the next one. Records with equal numbers share the load, and senders pick between them at random.

A Google Workspace domain, for example, returns smtp.google.com with preference 1. Microsoft 365 domains point to a host ending in mail.protection.outlook.com.

Common Problems

• No MX records found: senders fall back to the domain's A or AAAA record (RFC 5321). If that host doesn't run a mail server, mail bounces.
• MX pointing to an IP address or a CNAME: the target has to be a hostname with its own A or AAAA record. Many senders reject other targets.
• Old records left after a migration: if the previous provider's MX is still listed, some mail lands in a mailbox nobody reads.
• Null MX (0 .): a single record with an empty host means the domain accepts no mail at all (RFC 7505). Use it on domains that never receive email.

Changing MX Records

You edit MX records at your DNS host, which is often your registrar or a provider like Cloudflare. Lower the record's TTL a day before a switch so resolvers drop the old answer sooner. Then add the new provider's hosts and remove the old ones once the new mailbox receives test messages.

MX records only control incoming mail. Outgoing mail is checked against SPF, DKIM and DMARC records, which you can test with the SPF record lookup.