MX record lookup
Find the mail servers that accept email for any domain — in priority order, straight from your browser over encrypted DNS-over-HTTPS. Null MX and no-MX domains are surfaced honestly. No install, nothing stored.
Reads the live MX records for a domain over encrypted DNS-over-HTTPS — the mail servers that accept email for it, in priority order. Nothing is stored.
Queries run in your browser via Cloudflare DNS-over-HTTPS. We don't log the domains you look up. MX records tell you which servers accept mail for a domain — deliverability also depends on SPF, DKIM, DMARC, and reputation.
What an MX record lookup shows you
MX record
An MX (Mail eXchanger) record names a server that accepts email for a domain, along with a priority number that sets the delivery order. A domain can publish several, so mail has fallbacks if the preferred server is down.
[email protected], their server looks up
example.com's MX records and connects to the lowest-priority host that answers. Here's
what each column above means.
- Priority
- A preference number (also called the MX preference). Lower is tried first; equal values are load-balanced. It sets the delivery order, not a quality ranking.
- Mail server
- The hostname of a mail exchanger that accepts email for the domain. It must resolve to an A or AAAA record — an MX record may not point at a CNAME or an IP directly.
- TTL
- How many seconds a resolver may cache the record before asking again. Lower TTLs let mail-server changes take effect faster.
How the lookup works
When you enter a domain, your browser sends a query for its MX records directly to a public DNS-over-HTTPS (DoH) resolver — Cloudflare by default, or another you pick. Each MX answer comes back as a priority number and a mail-server hostname; we split them, sort by priority (lowest first), and show each with its TTL. The request is encrypted in transit, and because it goes straight from your browser to the resolver, we never see or store the domains you look up.
Priority, fallback, and the special cases
The priority number decides order, not preference in the everyday sense: senders try the lowest number first and fall back to higher ones only if it's unreachable. Records that share a priority are treated as equal, so mail is spread across them. The absolute values don't matter — a set of 10, 20, 30 behaves exactly like 1, 2, 3.
Two results look empty but mean very different things, so the tool separates them:
A domain with no MX records at all is different. Under RFC 5321 a sender may fall back to the domain's A or AAAA address and try to deliver there — an "implicit MX." If no address record is reachable either, mail simply can't be delivered. The tool spells out which case you're looking at rather than showing a bare empty result.
Honest limitations
MX records answer exactly one question: where is mail for this domain accepted? They do not prove a message will actually be delivered or land in the inbox. That depends on things DNS can't show you here — SPF, DKIM, and DMARC authentication, the sending IP's reputation, and the receiver's content filtering. A domain can have perfect MX records and still bounce or junk your mail.
A few more caveats worth knowing: an MX target must resolve to an A/AAAA record and must not be a
CNAME or a raw IP (a common misconfiguration); different resolvers can briefly disagree right after a
change, because records are cached until their TTL expires; and this tool reads what a public resolver
returns, which is the same data dig would show — no more, no less. To check a domain's
mail authentication, use the DMARC & SPF checker.
MX record lookup — frequently asked questions
What is an MX record?
An MX (Mail eXchanger) record tells sending mail servers which hosts accept email for a domain, and in what order to try them. Each record has a priority number and a mail-server hostname. When someone emails [email protected], the sender looks up example.com's MX records and connects to the lowest-priority server that answers.
What does the priority number mean?
Priority (the MX preference) sets delivery order, and lower wins. A sender tries the lowest number first; if that server is unreachable it falls back to the next-lowest, and so on. Two records with the same priority are treated as equal and the sender picks between them, spreading load. The numbers are relative — 10 and 20 behave the same as 1 and 2.
The domain has no MX records — can it still receive mail?
Possibly. Under RFC 5321, if a domain publishes no MX record a sender may fall back to its A or AAAA address and attempt delivery there (an "implicit MX"). If there's also no reachable A/AAAA record, mail can't be delivered. Publishing explicit MX records is the reliable way to receive email.
What is a null MX record?
A null MX is a single MX record with priority 0 and the host set to "." (the root). Defined in RFC 7505, it is an explicit declaration that the domain accepts no email at all. Well-behaved senders see it and reject the message immediately instead of retrying for days. It's the correct way to mark a domain as non-mail — send-only or parked domains often use it.
Does a valid MX record mean my email will be delivered?
No. MX records only say where mail is accepted — they don't prove a message reaches the inbox. Deliverability also depends on SPF, DKIM, and DMARC authentication, the sending IP's reputation, and content filtering. Use the DMARC & SPF checker to verify a domain's mail authentication is set up correctly.
Why can't an MX record point to an IP address or a CNAME?
By specification, an MX record's target must be a hostname that resolves to an A or AAAA record — not a literal IP, and not a CNAME alias. Pointing an MX at a CNAME is a common misconfiguration; some senders tolerate it, but it's non-conformant and can cause intermittent delivery failures. Point MX records at real A/AAAA hostnames.