MX Lookup
Mail exchanger records with priorities.
Use the MX Lookup tool
What this mx lookup does
MX records tell the internet which servers accept email for a domain, and in what order to try them. A lower priority number means a preferred server; if it is unreachable, sending servers move to the next priority.
This lookup queries Cloudflare's DNS-over-HTTPS resolver directly from your browser and lists the exchanges in priority order. It also recognises a null MX record (priority 0, exchange “.”), which is a deliberate statement that a domain accepts no mail.
Why use it
- Check that a domain's mail is routed to the provider you expect.
- Diagnose email delivery problems after a DNS change.
- Confirm which server is primary and which is backup.
How to use it
- 1Enter the domain, without a scheme or path.
- 2Run the lookup.
- 3Read the priority and exchange for each record.
Worked examples
Two servers
Input
yourdomain.com with priorities 10 and 20
Output
The priority-10 server is tried first, then the priority-20 server.
Null MX
Input
A domain that does not accept email
Output
0 . — explicitly no mail service.
Common mistakes
- Looking up MX on a subdomain that has none; mail for subdomains often falls back to the apex.
- Treating the highest priority number as the primary server; lower is preferred.
- Forgetting that MX targets must resolve to A or AAAA records themselves.
Frequently asked questions
What does priority mean?
It is a preference order. Lower numbers are tried first. A backup server usually has a higher number.
Why are there no MX records?
A domain can still receive mail through an implicit fallback to its A record, but RFC 7505 discourages relying on that. No MX usually means mail is not configured.
Does this test whether mail actually arrives?
No. It reads DNS. Delivery also depends on SPF, DKIM, DMARC, server availability and reputation.