MX Record Lookup
Look up MX mail exchanger records for a domain, showing mail server priority and hostname
Usage
• Domain: enter a bare domain without https:// (e.g. gmail.com)
• Lower priority numbers indicate higher-priority mail servers
• MX records determine which server receives email for this domain
What MX record lookup is for
An MX (Mail Exchanger) record lookup queries DNS for the mail exchange records of a domain, returning each mail server hostname and its priority. MX records tell the Internet where to deliver email addressed to a domain — the server with the lowest priority number receives mail first.
Common uses include verifying that mail server configuration is correct after a migration, confirming that a newly added mail service has propagated, diagnosing mail delivery failures by checking which server is expected to receive mail, and auditing a domain's email infrastructure before setting up SPF, DKIM, or DMARC.
Frequently asked questions
What does the priority number mean?
Lower numbers have higher priority. Sending servers try the lowest-numbered MX record first. Multiple records with the same priority are tried in random order for load balancing.
Why is there no MX record for my domain?
RFC 5321 defines implicit-MX fallback when no MX exists and usable address records are available. This differs from a published Null MX, which explicitly states that the domain does not accept mail.
I added an MX record — when will it take effect?
There is no universal propagation deadline. Previous record TTLs, negative caching, authoritative configuration and resolver policies affect when a changed MX record is observed. Compare authoritative and recursive answers at the relevant query time.
What should I check after changing MX records?
After MX records propagate, also verify that SPF includes the new mail server and that DKIM keys are published for the new provider. Use the SPF, DKIM, and DMARC tools to check email authentication configuration.
References and result limitations
Online results reflect the queried source or probe state at that time. Record the target, time, nodes or data source, and parameters when citing them. A single result does not establish continuous availability everywhere.
- RFC 5321 — Simple Mail Transfer Protocol
- RFC 7505 — Null MX — Domains That Accept No Mail
- RFC 1035 — Domain Names — Implementation and Specification
These references explain protocol or format rules; they do not endorse results produced by this site.