Free tool
DNS & lookupMX Record Lookup
Inspect MX priorities and mail exchange hosts for any domain. Confirm Microsoft 365 or on-prem mail routing before you cut over email.
Looks up public internet data for the target you enter. We do not store results.
Free toolEmail delivery fails quietly when MX records point at the wrong host or carry the wrong priority. This free MX record lookup shows every published mail exchanger, sorts by preference, and resolves exchange IPv4 and IPv6 addresses so IT students and network administrators can verify routing. Use it during Microsoft 365 migrations, CCNA-adjacent DNS labs, and network administration tickets where “mail is down” usually means DNS, not the client.
How to use the MX Record Lookup
- 1
Enter the apex domain that receives mail, for example contoso.com.
- 2
Tap Lookup MX to list priorities and exchange hostnames.
- 3
Read the resolved IPv4 examples for each exchange, then compare them with your Microsoft 365 or mail gateway documentation.
Why MX checks belong in every mail cutover
MX records tell the world where to deliver SMTP. Lower priority numbers win first; higher numbers are backups. Microsoft 365 tenants typically publish an exchange under mail.protection.outlook.com. If you skip an MX check, you risk sending production mail into an old appliance. Network engineers and Cisco networking students who practise reading MX tables catch those mistakes before users do.
Microsoft 365 MX example
Many Microsoft 365 domains publish a single MX such as contoso-com.mail.protection.outlook.com with priority 0. Look up outlook.com or your tenant domain here, confirm the exchange hostname, and note the IPv4 addresses behind it. That is the same validation step admins run after DNS changes.
Guides and next steps
Privacy note
We query public DNS MX records for the domain you submit. We do not store lookup history.
Frequently asked questions
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