Look up Mail Exchange (MX) records for any domain. Find mail servers, their priority order, and TTL values instantly.
A Mail Exchanger (MX) record is a DNS resource record that specifies the mail server responsible for accepting email for a domain. When you send an email to user@example.com, your mail server queries DNS for example.com's MX records to find out which server(s) to deliver the message to.
MX records have a numeric priority value. Lower numbers have higher priority. If the primary mail server is unavailable, delivery is attempted on the next lowest priority server.
The hostname in an MX record must resolve to an A or AAAA record (not a CNAME). The receiving server listens on port 25 (SMTP) for incoming mail.
Most MX configurations route mail through spam filtering gateways (e.g. Google, Proofpoint) before passing it to the actual mailbox server.
Multiple MX records with different priorities provide failover — if the primary server is down, sending servers queue and retry via lower-priority servers.
Common causes include missing or misconfigured MX records, an MX record pointing to a CNAME, the mail server refusing connections on port 25, or the sending IP being blacklisted.
Yes. If no MX record exists, some senders will fall back to delivering directly to the A record of the domain. This is unreliable and not recommended for production email.
It shows the hostname of the mail server. For Google Workspace domains this is typically aspmx.l.google.com.