MX record lookup

What an MX record is

A mail exchanger (MX) record is the DNS entry that tells sending servers where to deliver email for a domain. Each record has a host name and a priority number. Senders try the lowest number first and move to the next one if it does not answer, which is how domains run backup mail servers.

No MX record usually means no email. The mail standards do allow a fallback: if a domain has no MX but does have an address (A or AAAA) record, senders may try delivering to the domain itself. In practice few domains rely on this, so the lookup flags it separately.

How to read the result

• Accepts email: at least one MX record exists, so the domain can receive mail. It does not prove a particular mailbox exists.
• Null MX: the domain publishes a single MX record of ".", the RFC 7505 way of saying it never accepts mail. example.com does this.
• Fallback only: no MX record, but an address record exists. Treat addresses on it with caution.
• Domain not found: there are no DNS records at all, so every address on the domain will bounce.

SPF and DMARC

SPF lists the servers allowed to send mail for a domain, and DMARC tells receivers what to do when a message fails authentication. They matter for sending, not receiving, but their absence on a domain you are about to email often points to a parked or abandoned domain. If they are missing on your own sending domain, fix that first: major mailbox providers now expect both from bulk senders.

MX lookup versus email verification

An MX lookup answers whether a domain can receive email. Verification goes one step further and asks that mail server whether a specific mailbox exists, then adds catch-all, disposable and role-address checks. Use the free email checker for one address, or the bulk verifier for a list.