About the MX Lookup
The MX lookup tool queries a domain's DNS for its MX (Mail Exchanger) records and lists every mail server ordered by priority, so you can see exactly which hosts are responsible for receiving that domain's email. For each mail server it also resolves the hostname to its A (IPv4) and AAAA (IPv6) addresses, giving you a complete picture in one view.
Use it to debug mail delivery, verify that a domain's MX records point where you expect after a migration, or confirm a backup mail server is configured. The lookup is performed on the server and queries live DNS, and the tool warns you when a domain has no MX records at all, which is a common cause of bounced mail.
How to use it
- Enter the domain name you want to check (for example example.com).
- Run the lookup to fetch the domain's MX records.
- Review the mail servers listed in priority order (lowest number is tried first).
- Check the resolved A/AAAA addresses for each mail host.
- Note any warning that the domain has no MX records.
Examples
- Look up gmail.com to see Google's mail servers listed by priority with their IP addresses.
- After moving email to a new provider, verify the domain's MX now points to the new host instead of the old server.
- Check a domain that bounces mail and discover it returns a no-MX-records warning, explaining the delivery failure.
Frequently asked questions
What is an MX record?
An MX (Mail Exchanger) record is a DNS entry that tells other mail servers which hosts accept email for a domain. Each record has a priority value, and senders try the lowest-priority (most preferred) server first.
How does MX priority work?
The priority is a number where lower means higher preference. Sending servers attempt the mail host with the lowest number first and fall back to higher-numbered hosts if it is unavailable.
Why does a domain have no MX records?
Some domains simply do not receive email, or the records were never configured. Without MX records, most mail servers will fail to deliver, which is why the tool shows a warning.
Is this lookup done in my browser or on the server?
The DNS query runs on the server, which then returns the MX records and resolved IP addresses to you. The domain name you enter is sent to the server to perform the lookup.
What is the difference between an MX record and an A record?
An MX record names the mail server hostname for a domain, while an A or AAAA record maps a hostname to an IP address. This tool shows both: the MX hosts and the addresses they resolve to.
Can multiple MX records share the same priority?
Yes. When several MX records have equal priority, sending servers distribute connections between them, which provides load balancing and redundancy.