The address book for incoming mail
When someone sends email to hello@example.org, the sending system uses the part after the @ to find the receiving mail service. The domain’s MX records provide the mail-server hostnames. A website and its email can be hosted by different companies, so changing a website’s address does not necessarily change email delivery.
Read the three fields together
For an illustrative record such as 10 mail.example.org, 10 is the preference and mail.example.org is the destination hostname. The TTL tells a resolver how long an answer may remain cached. Our tool shows the remaining TTL reported by the selected resolver, which may be lower than the value you originally set.
Keep the hostname exactly as your mail provider specifies. A trailing dot marks an absolute DNS name; this tool removes it from ordinary hostnames for readability, while keeping the dot in a Null MX record.
Make a useful first lookup
- Enter the receiving domain, not the sender’s domain.
- Compare the listed hostnames with the records shown in your mail provider’s setup instructions.
- If you recently changed them, repeat the lookup with the second resolver.
- Copy the records or download JSON to include a timestamped result in a support request.
Different answers need different next steps
No MX records: no explicit mail route was returned; investigate the domain’s intended email setup. Null MX: the domain explicitly opts out of incoming mail. NXDOMAIN: the queried name was reported as nonexistent. DNS error: the resolver could not produce a usable answer; this is not the same as finding no records.
A DNSSEC “validated” result means the resolver set its authenticated-data flag. If that flag is absent, the tool reports “not confirmed”; it does not label the domain insecure or broken.
Know the boundary of the result
An MX record is a routing instruction. It does not prove that the destination server is online, that TLS is configured correctly, that a mailbox exists or that a sender will pass spam checks. For a delivery issue, keep the original bounce message and continue with the troubleshooting guide.