MX Lookup
Check MX records for a domain through DNS over HTTPS to inspect the mail servers associated with email delivery.
Your result will appear here.
MX Lookup online
Look up a domain's MX records — the mail servers that accept its email, with their priorities — through Google's public DNS-over-HTTPS resolver.
How to use this tool
- Enter a domain name such as example.com.
- Click Run Tool. The MX records return with a preference number in front of each mail server.
- Lower preference is tried first; equal preferences share the load.
Common uses
Verifying a new mail provider is wired up (Google Workspace, Microsoft 365, a self-hosted server), diagnosing "mail to this domain bounces", checking a failover server exists, and auditing a domain you are migrating before the old provider is cancelled.
How it works
The tool queries the MX record type through dns.google/resolve. Each answer line carries a preference value and a hostname: senders try the lowest preference first and fall back upward when a server is unreachable. Note what MX is not: it names the servers for a domain's incoming mail only. Whether mail from the domain is trusted is a separate question answered by SPF, DKIM and DMARC records.
Worked example
A domain on Google Workspace answers with five records in the classic pattern — preference 1 for the primary (ASPMX.L.GOOGLE.COM) and 5/5/10/10 for the alternates. If your lookup shows only some of them, DNS is still propagating or the zone edit was partial; senders will deliver to whichever subset they can see, which is why half-migrated mail "mostly works" and then loses messages.
Privacy and browser processing
The lookup is sent to Google's public DNS-over-HTTPS resolver over HTTPS; nothing is stored by this site.
Frequently asked questions
What do the preference numbers mean?
Priority order. Senders attempt delivery to the lowest number first and move up the list on failure. Equal numbers mean "either is fine" and senders pick between them, which is how simple load sharing is done.
There are no MX records. Can the domain still receive mail?
Technically yes: if no MX exists, senders fall back to the domain's A record (the implicit MX rule). It is legacy behaviour, unreliable with modern setups — publish explicit MX records for any domain that receives mail.
Mail still goes to the old provider after my change. Why?
Caching. Resolvers hold the old MX set until its TTL expires, and the sending side caches too. Expect the full TTL window of mixed delivery after any MX edit, and keep the old mailbox alive through it.
Does an MX lookup test that the server works?
No — it reads DNS only. A listed server can be down, misconfigured or rejecting your domain and the lookup will still look perfect. Delivery problems beyond DNS need an SMTP-level test.
Is my query private?
The lookup goes over HTTPS to Google's public resolver under its logging policy. Nothing is stored by this site.