MX Lookup

MX records tell the world which servers receive email for your domain. They are listed in priority order: the lowest preference number is tried first, then higher numbers are used as backups.

If your domain has no working MX records, mail sent to your team may bounce or disappear into retry queues. If you also send email from this domain, check your authentication with the SPF Check.

Priority / preference - the order senders try your mail servers. Lower numbers are tried first.

Mail server hostname - the server name that receives mail, such as aspmx.l.google.com.

Provider - the mail platform we recognize from the hostname, such as Google Workspace or Microsoft 365.

Reverse DNS (PTR) - a lookup from an IP address back to a hostname. It helps mail servers look legitimate.

Null MX - a single . mail server that says this domain intentionally does not accept email.

No MX records - the domain has nowhere explicit to receive email.

MX pointing to an IP address - MX records must point to hostnames, not raw IPs.

MX hostname that doesn’t resolve - mail may be routed to a server name with no address.

Missing reverse DNS - a common trust signal is missing, which can contribute to spam placement.

Implicit fallback to the A record - with no MX record, senders may try the website address instead. It can work, but it is fragile.

You can inspect the rest of the domain’s records with DNS Lookup.

Not by itself. Some providers, including Microsoft 365, commonly publish a single MX record for a domain. A short list is fine when the hostname resolves and the provider handles redundancy behind the scenes.