Free MX Lookup
Enter a domain to see which servers receive its mail, the order senders try them in, and whether each one returns an address.
Reading mail servers...
Could not check
No A or AAAA address returned for this host.
Address not checked.
What an MX Lookup Tells You
An MX lookup reads the mail exchanger records for a domain: the list of servers that accept its email, each with a priority number. A sender tries the lowest number first and moves down the list if that server does not answer.
This MX record checker sorts the records into that order and resolves each hostname, so a server name that returns no address is flagged. It also recognises the null MX, a record that says a domain takes no mail. MX only covers incoming mail. For SPF, DKIM and DMARC on the same domain, use the email deliverability checker.
- Enter the domain from the email address, the part after the @.
- We ask a public resolver for its MX records and sort them by priority.
- Each mail server hostname is resolved to its A and AAAA addresses.
- Read the verdict, and fix any host flagged as having no address.
What this check settles
- Who handles the mail: the hostnames usually show the provider, such as Google or Microsoft.
- Which server is tried first: the order comes from the priority numbers, not the order in your DNS dashboard.
- Whether mail has a destination: a listed server with no address cannot receive anything.
MX Setups Explained
What you see in the records, and what senders do with it.
| Setup | What is published | What senders do | Result |
|---|---|---|---|
| Primary | The lowest priority number | Tried first. Priority is a preference, not a score, so 0, 1 and 10 all mean first when they are the lowest on the list. | Receives mail |
| Backup | Higher priority numbers | Tried when lower numbers do not answer. Two servers with the same number share mail between them. | Fallback |
| Null MX | A single record: 0 . | Defined in RFC 7505. It declares that the domain takes no mail, which suits parked and web-only domains. | No mail, by design |
| No MX | Nothing published | Senders fall back to the domain's own A or AAAA address, under the rules in RFC 5321. Mail usually fails there, often slowly. | Usually fails |
How to Read the Result
Servers are listed in the order a sender would try them.
The verdict
The headlineWhether every server we checked returns an address, whether the domain declares it takes no mail, or whether no MX records exist at all.
Hostnames
The serversThe mail servers themselves. A name ending in google.com or outlook.com tells you who runs mail for the domain.
Priority and TTL
The orderLower priority numbers are tried first. TTL is how many seconds a resolver may cache the answer, so it shows how long a change can take to reach senders.
Addresses
The destinationThe A and AAAA addresses behind each hostname, for the first six servers. A host with no address is flagged, and anything past six shows as not checked.
What an MX Record Is
An MX record names a mail server for a domain and gives it a priority. When someone emails you, their server looks up your MX records and connects to the hostname with the lowest number.
A typical record reads 10 mail.example.com: priority 10, and that host receives the mail. It has nothing to do with where your website is hosted, so the two can sit with different companies.
How to Change Mail Providers Safely
Changing MX records moves your incoming mail, so a small amount of preparation prevents lost messages.
The usual sequence:
- Lower the TTL on the MX records a day ahead, so the switch takes effect quickly.
- Set up mailboxes at the new provider before anything points at it.
- Replace the old records and remove any you are not keeping. A leftover server still receives mail.
- Update SPF and DKIM for the new provider, then check propagation.
Where MX Records Go Wrong
MX mistakes tend to be quiet: mail goes missing and nothing shows an error. The common cases:
- An old provider left in the list after a migration, so some mail still lands in mailboxes nobody reads.
- An MX pointing at a CNAME. The standards require the target to be a hostname with its own address records, and some senders refuse otherwise. A DNS lookup shows what the name holds.
- An IP address in the value. An MX target must be a hostname, so publish an A record and point the MX at that.
- A trailing dot left off in a zone file, which turns mail.example.com into mail.example.com.example.com. It shows up here as a host with no address.
Why MX Records Matter
Mail can be redirected
Whoever an MX record names receives the domain's mail, password resets included. An unexpected change deserves attention straight away.
Lost mail is silent
Customers see a bounce or nothing at all, and you see an empty inbox. A broken MX can run for days before anyone connects the dots.
It names the provider
One lookup shows who runs a domain's mail, which helps when you inherit a domain or need to know where to log in.
A clean signal on spare domains
A null MX on a domain that receives no mail tells senders to stop trying, instead of leaving the outcome undefined.
Who Checks MX Records
The same list of servers answers a different question for each team.
IT & Email Admins
Confirm the cutover during a migration, and trace why mail to a domain is bouncing.
For DNS monitoringSecurity Teams
Check that mail for each of your domains goes only to providers you approved.
For IT & MSPsEmail Marketers
Confirm a reply-to domain can receive mail before a campaign goes out.
For marketersAgencies
Record a client's mail setup before a site move, so a DNS change does not take their email with it.
For agenciesRelated Email & DNS Tools
MX covers mail coming in. These cover the rest of the setup.
Check deliverability
Grade MX, SPF, DKIM and DMARC together for the full picture.
Email deliverability checkerFrequently Asked Questions
Common questions about MX records and how to check them.
How do I check my MX records?
Enter your domain in the MX lookup above. It lists your mail servers in priority order and shows the addresses behind each one. On the command line, dig MX example.com returns the same records.
What does MX priority mean?
It is the order senders try your servers in, lowest number first. Only the relative order matters, so 1 and 5 behave the same as 10 and 50. Servers with equal numbers share the mail.
What happens if a domain has no MX records?
Senders fall back to the A or AAAA address of the domain itself. Unless a mail server runs there, delivery fails, often after hours of retries. If the domain takes no mail, publish a null MX.
What is a null MX record?
A single MX record with priority 0 and a target of a lone dot, defined in RFC 7505. It says the domain does not accept mail, so senders can fail immediately rather than retry.
Can an MX record point to a CNAME?
It should not. The standards require an MX target to be a hostname with its own address records. Many servers tolerate an alias, but some refuse it, so point the record at the real hostname.
Can an MX record point to an IP address?
No. The value must be a hostname. Create an A record such as mail.example.com for the address, then point the MX record at that name.
How long do MX record changes take?
Up to the TTL of the old record, which the result shows, because resolvers may cache the previous answer until it expires. Lower the TTL a day before a planned change to shorten this.
Do MX records affect my website?
No. Web traffic follows A, AAAA and CNAME records, and mail follows MX. That is why a site and its mail can be hosted by different companies.
Does a working MX record mean my mail will arrive?
It means senders can find your servers. Sending from the domain depends on other records: SPF, DKIM and DMARC decide whether your outgoing mail is trusted. The email deliverability checker covers those.
Start Monitoring & Catching Domains Today
Join founders, agencies, and domainers already protecting their portfolio. Your first 5 domains are free.
No credit card required • Cancel anytime
Guides for domain operators
Deep dives on domain names, DNS, SSL, acquisitions and portfolio management.
All guides →
4 Letter Domains: The Complete LLLL Investing Playbook
4 letter domain names represent one of the most liquid segments of the domain aftermarket. All 456,976 possible .com combinations are registered.
.SI Domain: Slovenia's 30-Year-Old ccTLD Is Suddenly Super Intelligence
What is the .SI domain? Learn how Slovenia's country-code TLD went from 10 registrations in 1992 to a 2,199% surge in September 2026, and why 'super intelligence' made .SI the new .AI.
Infringing Domains: Detecting, Monitoring, and Recovering
Your domain is your storefront. Every day, someone registers a lookalike of it, to skim your traffic, phish your customers, or hold it for ransom. This guide covers what infringing domains are, how to find them before they hurt you, and exactly what to do when you do.