MX Lookup
This free MX lookup shows which mail servers receive email for a domain, in priority order, and flags the setups that make mail bounce.
What is an MX record?
An MX (mail exchanger) record tells the world which servers accept email for a domain. Without one, mail to that domain bounces or gets lost.
Each MX record has a priority number and a hostname. Senders try the lowest number first and move to the next if it doesn't answer.
How to read the results
Servers are listed from first choice to last. Each hostname should resolve to at least one IP address. If it doesn't, mail sent to it bounces.
We also spot common providers like Google Workspace and Microsoft 365, and warn about MX records that point to a CNAME or an IP address, which some senders refuse.
Frequently asked questions
What does the MX priority number mean?
Lower numbers are tried first. Two records with the same number share the load, and higher numbers act as backups.
Can a domain have no MX record?
Yes, but then senders fall back to the domain's A record, which is rarely what you want. A domain that never receives mail should publish a null MX ("0 .") instead.
Why is an MX pointing to a CNAME a problem?
The email standard (RFC 5321) says MX targets must be real hostnames. Many servers cope with a CNAME, but some reject the mail, so point the MX at the final hostname.
I changed my MX records. Why is mail still arriving at the old server?
Senders cache MX records for their TTL. Leave the old mailbox running until the old TTL has passed, usually a few hours, so nothing gets lost in between.