Free MX lookup
Look up a domain's mail servers.
See the MX records for any domain in priority order, which provider handles its inbox, and whether it can actually receive replies and bounces.
About MX records
Where a domain's email goes
What MX records do
MX (mail exchanger) records tell other servers where to deliver email for your domain. Each record has a host name and a priority: the lowest number is tried first, and the others are backups.
Why senders should care
Even if you only send from a domain, it needs somewhere to receive replies and bounce messages. Some receivers also check that a sending domain can receive mail before they trust it.
Common mistakes
MX records must point at a host name, never an IP address. After moving to a new provider, leftover MX records for the old one split your mail between two places.
Questions
MX records, answered
What does MX priority mean?
Lower numbers are tried first. Servers with the same number share the load, and higher numbers are backups used when the first ones don't answer.
Can a domain have no MX record?
Yes, if it never receives mail. A null MX record (0 .) says so on purpose. Without any MX, senders fall back to the domain's A record, which rarely works.
How long do MX changes take?
Usually minutes, up to a few hours depending on the TTL of the old records. During the switch, mail can arrive at either provider.
Which provider does a domain use?
The checker recognizes common providers from their MX host names, such as Google Workspace, Microsoft 365, Zoho Mail, Proton Mail and Fastmail.
Stop fixing DNS by hand.
SmartMailing gives you the records for your sending domain and checks them for you.