Checking a domain’s MX records is a first step toward understanding how it receives email. It helps when you review a list before a campaign, investigate a typo, or check your own domain settings. It does not establish whether a particular address exists.
What is an MX record?
An MX record identifies the servers that receive email for a domain. Look up the part after the at sign: for person@company.example, that is company.example. This is a fictional domain used only to explain the process.
A response may contain several servers and preference numbers. Lower values take priority. Multiple destinations do not mean multiple mailboxes, and the records do not establish who uses an address.
How to check MX records without installing tools
Open an MX lookup tool and enter only the domain. You do not need to upload your whole list to investigate one domain, and you should never enter passwords. Use a domain you own when checking a configuration change.
Look up a domain’s MX records →
- Separate the domain from the address; leave out the part before the at sign.
- Check for spaces and common spelling mistakes.
- Review the returned server names and their preference values.
- Keep the observation date if you plan to compare a later change.
A hypothetical response might list mail.company.example with preference 10 and another destination with preference 20. These are documentation names, not actual responses or servers to configure. When changing your own records, use the values supplied by your mail hosting service.
What an empty response or Null MX means
An absence of MX records does not always mean a domain cannot receive email: SMTP allows an implicit destination based on address records. A Null MX, published as 0 ., explicitly declares that the domain accepts no mail. This differs from a temporary DNS lookup failure.
Preserve that distinction when a tool cannot complete its lookup. Do not delete a contact solely because a network request timed out. Review the reason, check the spelling, and decide whether a later attempt is appropriate.
A valid MX and a valid mailbox are different questions
A domain can have configured mail servers and still reject the recipient you want to contact. It can also accept every address or refuse a conclusive check. A list should not be marked ready to send just because all its domains have MX records.
- Domain configuration helps describe the email route.
- A recipient response provides an observation about that address when the server allows a check.
- Identity and consent require a separate process; an MX lookup does not establish either.
Using MX information in your contact list
Start by correcting input with the person who supplied it. If a domain looks misspelled, suggest a correction and ask for confirmation instead of silently changing the address. Then check the complete email address so format errors, rejections and undetermined cases remain separate.
ByeBouncer lets you review one email or process lists of up to 5,000 emails per job. Each address gets its own result so you can decide whether to request a correction, check again later, or continue your workflow. No message is sent during the check, and a positive response does not guarantee delivery or a read.
See how email verification works →