MX Record Checker
Enter a domain to see which mail servers accept email for it, in the order senders will try them, and whether each server name resolves correctly.
- Email security
- Live check
- Free, no sign-up
- Results are not published
Run MX Checker
At a glance
- What it checks
- List the mail servers for a domain in priority order and check that each one resolves to a public address.
- Data source
- MX and address records from public DNS-over-HTTPS resolvers.
- Freshness
- Live check; results are cached for up to 10 minutes
- Limits
- Mail servers are not contacted, so deliverability and SMTP behaviour are not tested. Methodology
- Cost
- Free, no account needed
Understanding the result
What MX records do
Mail exchanger (MX) records tell sending servers where to deliver email for a domain. Each record has a priority number and a hostname. Senders try the lowest number first and fall back to higher numbers if that server is unavailable. Records with the same priority share the load.
example.com. MX 10 mx1.example.net.
example.com. MX 20 mx2.example.net.
The hostname in an MX record must have its own A or AAAA record. An MX record cannot point directly at an IP address.
What the checker reports
The tool looks up the domain's MX records, sorts them by priority, and resolves up to ten mail server names to their IPv4 and IPv6 addresses. The table shows priority, hostname, TTL and addresses.
- MX present (PASS): the domain publishes mail servers.
- No MX records (WARNING): senders may fall back to the domain's A record, which rarely hosts a mail server. If the domain does not exist at all, the finding says so.
- Null MX (INFO): a single record of
0 .declares that the domain accepts no email, as defined in RFC 7505. That is correct for domains used only for websites. - Resolvable (PASS or FAIL): whether every mail server name resolves to an address.
- CNAME target (WARNING): an MX hostname is an alias. The standards say MX targets should not be CNAMEs, and some senders will refuse them.
- Private address (WARNING): a mail server resolves to an address such as
192.168.1.10that cannot be reached from the internet. - Single mail server (INFO): there is no backup MX. Many hosted mail services are redundant behind one name, so this is only a note.
Common problems
The most frequent issue after moving to a new email provider is leftover MX records for the old one. Senders pick among all published records, so some mail keeps going to the old service. Remove records that no longer apply, and copy the provider's values exactly, including the trailing dot if your DNS editor requires it.
Another common mistake is a typo in the mail server hostname, which the resolvability check catches. If you just changed records, remember that senders may use cached values until the old TTL expires.
Going further
MX records get mail delivered to you; they do nothing to stop others from forging your address. Check the SPF Checker and DMARC Checker for that, or run the Email Security Checker to review everything in one pass. This tool reads DNS only; it does not open SMTP connections to your mail servers or test whether they accept messages.
Frequently asked questions
What priority numbers should I use?
The numbers only matter relative to each other. Use whatever your email provider specifies. Lower means preferred, and equal numbers mean senders spread mail across those servers.
Do I need a backup MX server?
Usually not with a hosted email service, since those are already redundant. Sending servers also queue and retry mail for some time if your server is temporarily down.
Can I use MX records on a subdomain?
Yes. A subdomain such as mail.example.com or support.example.com can have its own MX records, and you can check it here by entering the full name.
My domain does not send or receive email. What should I publish?
A null MX record (0 .), an SPF record of v=spf1 -all and a DMARC policy of p=reject. Together they tell other servers to reject mail that claims to come from the domain.