An MX (Mail Exchanger) record is a DNS record that tells sending mail servers which hosts are responsible for receiving email for your domain. Each MX record points to a hostname and carries a preference value, where a lower number means higher priority.
MX records matter because they are the first step in inbound mail routing. When a server has mail for you@example.com, it looks up the MX records for example.com, then connects to the listed host with the lowest preference value, falling back to others if that host is unavailable. The target of an MX record must be a hostname that resolves to an address, never an IP literal, and it should not point at a CNAME.
You can publish several MX records for redundancy and load distribution. If no MX record exists, some senders fall back to the domain's address record, but relying on this is discouraged.
MX records are also relevant to security: MTA-STS and DANE protect the connection to your MX hosts, and your inbound platform shapes how SPF and DKIM behave. To check your MX records, query DNS for the MX type and confirm the hostnames resolve and accept mail on port 25.
Check it on your domain
- MX Record Checker: looks up the mail servers for a domain.
- DNS Record Checker: looks up any DNS record type for a host.
- MTA-STS Checker: checks the MTA-STS record and the hosted policy file.