MX Records Explained for Marketers: What They Are and How to Check Them
MX records tell the world where a domain receives mail. What they are, what a missing record means for your list and how to look one up in seconds.
You do not need to be an engineer to understand MX records, and understanding them explains many bounces. An MX record is a line in a domain's settings that says which mail server receives the mail for that domain.
The postal address of a domain
When you send to [email protected], your mail server looks up the MX records of example.com. They list one or more mail servers, each with a priority number. Your server tries the lowest number first and moves on if it does not answer. No MX record, no known place to deliver.
Why this matters for your list
- No MX record at all: the domain cannot receive mail in the normal way. Every address on it will bounce. This is common with typo domains and expired websites.
- An MX record that points nowhere: the domain looks fine but the server named does not answer. These bounce too, often later.
- Large providers: their records point to big, well-known mail systems, which tells you the domain probably receives mail but nothing about a single mailbox.
- Records that changed: when a company moves from one mail provider to another, the old addresses may stop working until the change is finished.
How to check one
- Take the part after the @ in the address.
- Look up its MX records with the free MX lookup tool.
- If the list is empty, the domain cannot receive mail and the address is not worth sending to.
- If there are records, the domain can receive mail. Whether the mailbox exists is a separate question.
What an MX check cannot tell you
A record proves the domain has a mail server. It does not prove that name@ exists. For that, a verifier asks the mail server itself. Run a single address through the email checker, or a whole list through bulk verification and let the tool check each domain and mailbox for you.
Related checks worth knowing
MX records say where mail goes in. SPF, DKIM and DMARC records say who is allowed to send mail from your domain and what to do with messages that fail. They protect your sending, while MX protects your list. The SPF, DKIM and DMARC checker reads those for your own domain.
Frequently asked questions
Can a domain receive mail without an MX record? Rarely, and not in a way you should rely on. Treat a missing record as a dead end.
How long do changes to MX records take? Usually minutes to a few hours, depending on the settings of the domain.
