MX lookup: see who receives a domain's email
Enter a domain or an email address to see its MX records in priority order, the mailbox provider behind them, and any security gateway that filters mail first.
Free, no signup. DNS lookups only: nothing is sent to the domain's mail server.
How to read the result
- Priority: lower numbers are tried first; equal numbers share the load.
- Mail server: the hostname that accepts mail, such as aspmx.l.google.com for Google Workspace.
- Mailbox provider: worked out from the server names. A company on Microsoft 365 shows Microsoft even though the domain is theirs.
- Security gateway: a filtering service in front of the provider, if one is visible in the records.
When an MX lookup helps
Before a campaign to a new list, a quick look at the biggest domains tells you whether they can receive mail at all and which providers you are really sending to. It is also the first thing to check when a whole company's addresses start bouncing: a moved or broken MX setup explains it at once.
An MX record only proves the domain accepts mail. Whether a particular person's mailbox exists is a separate question, answered by a live mailbox check such as our free email verifier.
MX lookup FAQ
What is an MX record?
A DNS record that names the servers accepting email for a domain. Each has a priority number; senders try the lowest number first.
What does it mean if a domain has no MX records?
It cannot receive email, so any address on it will bounce. Strictly, a domain without MX can fall back to its A record, but in practice a domain set up for mail publishes MX records.
Why does the provider matter?
Google, Microsoft and other providers each have their own rules for spam filtering, sending limits and verification. Knowing who runs a company's mail tells you whose rules your emails meet.
What is a security gateway?
A filtering service such as Proofpoint or Mimecast placed in front of the real mailbox provider. It can accept every message on the provider's behalf, which can make a mailbox harder to verify.
More free tools
- SPF checker
Check the SPF record, its DNS lookup count and the all mechanism.
- DMARC checker
Read the DMARC policy, reporting address and what to tighten.
- DKIM checker
Find a domain's DKIM keys and check their length and status.
- BIMI checker
See whether inboxes can show your logo, and what is missing.
- Disposable email checker
Find out if a domain is a throwaway inbox service.
- SPF record generator
Build a correct SPF record for the services that send your email.
- DMARC record generator
Create a DMARC record, from monitoring to full protection.
- Free email verifier
Check whether one address actually exists, with a live mailbox check.
A healthy domain is half of it. Verify the addresses too.
Free credits on sign-up. No card. You only pay for definite answers.
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