Input
Quick Examples
Results
Enter a domain and click Check MX to query mail exchange records.
Setting up MX records for Google Workspace and Microsoft 365
Both require adding specific MX records at your DNS provider. Copy-ready values below.
Google Workspace:
Priority Host
1 smtp.google.com
(Google consolidated in 2023 from 5 records to just this one; older docs still show aspmx.l.google.com, alt1.aspmx.l.google.com, etc. — those still work but the new single-record setup is preferred.)
Microsoft 365 / Exchange Online:
Priority Host
0 <your-tenant-prefix>.mail.protection.outlook.com
Tenant prefix: the part of your default onmicrosoft.com domain before the dot. Find it in Admin Center → Domains.
After updating DNS, MX records can take 15-60 minutes to propagate. Use our checker to verify — if it shows the old values, flush your resolver cache and re-check.
MX priority explained
MX records include a priority (preference) number. Lower = higher priority. Receivers try the highest-priority server first; if that fails, fall back to the next.
Priority Host
10 mx-primary.example.com
20 mx-backup.example.com
Common setups:
- Single server — one MX with any priority (often
10). - Active-backup — primary at
10, backup at20that queues mail if primary is down. - Load balancing — multiple MX records at the same priority — senders pick one randomly.
- Provider-managed — Google Workspace / Microsoft 365 / SendGrid manage priority/load balancing for you; one record per their instructions.
Frequently Asked Questions
How do I check the MX records of a domain?
Enter a domain. The MX checker queries DNS for Mail Exchange records, shows each server in priority order, resolves each to IPv4/IPv6, and checks if port 25 accepts SMTP — end-to-end email routing verification in one view.
What are MX records and why do they matter?
MX records tell the internet where to deliver email for a domain. Wrong or missing MX = email doesn't arrive. Priority lets you designate primary and backup mail servers (lower = higher priority). Essential for Google Workspace, Microsoft 365 or self-hosted mail setup.
How do I set up MX records for Google Workspace or Microsoft 365?
Google Workspace: point to `smtp.google.com` (priority 1). Microsoft 365: point to `<tenant>.mail.protection.outlook.com` (priority 0). Add the records at your DNS provider, wait for propagation (usually minutes, sometimes hours), then verify with our MX checker.
What's the difference between MX priority 10 and 20?
Lower number = higher priority. The receiving server tries priority 10 first; if it's unreachable, falls back to priority 20. Use multiple records for redundancy — e.g. Google Workspace gives you five with priorities 1, 5, 5, 10, 10.
Why do my emails bounce or end up in spam?
Common causes: missing or wrong MX, no SPF (our Email Header Analyzer confirms), no DKIM signing, no DMARC, IP blacklisted. Our checker catches MX issues — combine with a blacklist lookup and SPF/DKIM validator for full diagnosis.
Smarter quality checks. Faster deployments.
Better apps.
