MX Record Lookup
Look up the mail exchange (MX) records for any domain to see which email servers handle its incoming mail.
What are MX records?
MX (Mail Exchange) records specify which mail servers receive email for a domain. When someone sends to user@example.com, their mail server queries DNS for MX records, then connects to the highest-priority server listed. Without correct MX records, email delivery to your domain will fail.
Understanding MX priority
Lower priority numbers mean higher preference — the sending server tries the lowest number first, then falls back to higher numbers if unreachable. Many organisations have a primary MX at priority 10 and backup at priority 20. Google Workspace uses priorities 1, 5, 10, 20 and 30.
Common MX configurations
Google Workspace: aspmx.l.google.com and alt1-4.aspmx.l.google.com. Microsoft 365: a domain-specific subdomain of mail.protection.outlook.com. Zoho: mx.zoho.com and mx2.zoho.com. Self-hosted: typically a single MX record pointing to your mail server hostname.
Troubleshooting email delivery
If emails aren't arriving, check that MX hostnames resolve correctly, port 25 is open on those IPs, and TTLs haven't caused stale cache. Most email delivery failures trace back to incorrect MX records, expired SSL on the mail server, or port 25 being blocked by the hosting provider.