MX Lookup
Check which mail servers handle email for a domain, and in what priority order.
What Is an MX Record?
An MX (Mail Exchange) record tells the rest of the internet which mail server(s) are responsible for accepting email on behalf of a domain, and in what order to try them. Each MX record has a priority number — lower numbers are tried first — so a domain can list a primary mail server plus one or more backups that only get used if the primary is unreachable.
Why Check MX Records?
MX lookups are the first troubleshooting step when email isn't arriving: a missing or misconfigured MX record means mail has nowhere to go. They're also used to confirm a mail migration (e.g. moving from a self-hosted server to Google Workspace or Microsoft 365) has actually taken effect, and to verify you're sending test mail to the server that's really authoritative for a domain.
Frequently Asked Questions
Why does a domain have multiple MX records?
Multiple MX records provide mail delivery redundancy. Each has a priority number — lower numbers are tried first — so mail can fail over to a backup server if the primary is unreachable.
What does it mean if a domain has no MX record?
No MX record generally means the domain can't receive email at all — sending servers have nowhere to deliver to. Some mail transfer agents will fall back to a domain's A record as a last resort, but this isn't reliable and shouldn't be depended on.
Why do I see Google or Microsoft's mail servers in the MX results?
This is normal for domains using hosted email like Google Workspace or Microsoft 365 — the MX records point to the provider's mail infrastructure instead of a self-hosted server.
How long after changing MX records does email start working?
It depends on the record's TTL (time-to-live) and how quickly sending mail servers refresh their DNS cache — typically anywhere from minutes to 48 hours.
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