MX Record Lookup

Look up MX (mail exchanger) DNS records for any domain to see which servers receive inbound email and in what priority order. Lower priority numbers are preferred — mail flows to the lowest available MX first. Results include hostname, priority, and TTL via DNS-over-HTTPS. Essential when migrating to Google Workspace or Microsoft 365, debugging mail delivery failures, or confirming DNS after registrar changes. Read-only lookup — does not send email or validate mailbox existence.

How to Use the MX Record Lookup

Enter a domain to list its MX records sorted by priority with hostnames and TTL values.

  1. Open MX Record Lookup.
  2. Enter the domain that receives email (usually the apex, example.com).
  3. Click Run check to query MX records over DNS-over-HTTPS.
  4. Review the Mail exchangers table sorted by priority (lowest first).
  5. Confirm hostnames match your email provider's documentation (Google, Microsoft, etc.).
  6. Note TTL values if you plan further DNS changes — lower TTL before MX migrations.
  7. If results are empty, verify you edited the correct DNS zone and retry after propagation.

How inbound mail routing works

Sending MTAs perform an MX lookup on the recipient domain, sort by priority, and attempt SMTP delivery to the listed hosts. Incorrect or stale MX records are a common cause of mail bouncing or routing to the wrong provider.

Worked example

  • Google Workspace — expect multiple aspmx.l.google.com hosts with ascending priorities.
  • Microsoft 365 — typically *.mail.protection.outlook.com MX entries.
  • Migration cutover — old and new MX should not coexist long; lower priority on the new provider only when ready.

Common mistakes

  • Adding MX at the registrar while DNS is delegated elsewhere — edit the active zone only.
  • Typo in MX hostname — a single character breaks delivery even when web DNS works.
  • Forgetting accompanying SPF/DKIM/DMARC updates after MX changes.

Limitations

DNS snapshot only — does not test SMTP ports, TLS, or mailbox existence. Use SPF Record Checker and provider admin consoles for complete email setup validation.

FAQ

What is an MX record?

MX (Mail Exchanger) records tell sending mail servers which hosts accept email for a domain. Each entry has a priority number and a target hostname.

How does priority work?

Lower numbers are tried first. Priority 10 is preferred over priority 20. Equal priorities load-balance per RFC 5321 semantics.

Why do I see multiple MX rows?

Providers often publish several MX hosts for redundancy — for example Google's multiple smtp.google.com entries with different priorities.

Does this verify email actually delivers?

No. It only shows published DNS. Delivery also depends on SPF, DKIM, DMARC, firewall rules, and mailbox configuration.

Can a domain have no MX records?

Yes. Some domains accept no mail (null MX) or rely on A/AAAA fallback (discouraged). Empty results may mean no inbound mail is configured.

Which DNS resolver is used?

MX lookups use Google DNS-over-HTTPS by default in the implementation, returning public internet answers.

Should MX point to a CNAME?

RFC 2181 discourages MX targets that are CNAME aliases. Best practice is MX pointing to A/AAAA hostnames directly.

How does this relate to SPF?

MX says where mail is delivered; SPF (in TXT) says which servers may send mail as your domain. Both are required for healthy email auth.

Why might MX differ from what my provider dashboard shows?

DNS propagation delays, wrong zone edited (subdomain vs apex), or split DNS can cause temporary mismatches — use DNS Propagation Checker to compare resolvers.

Can I look up subdomain mail routing?

Yes — enter the full hostname (mail.example.com or example.com). MX for subdomains is independent of the apex domain.