MX Lookup ToolCheck Mail Server Records

Query MX records to verify mail server configuration, check email routing, and identify your email provider. Includes SPF, DMARC, and DKIM analysis.

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Understanding MX Records

MX (Mail Exchange) records specify which mail servers accept email for your domain. Each MX record consists of a priority value and a mail server hostname. When someone sends email to your domain, their mail server queries your MX records and attempts delivery starting with the lowest priority number.

How MX Priority Works

MX priority determines delivery order. Priority 10 is tried before priority 20. If the first server is unavailable, the sending server falls back to higher-priority servers. Common configurations include primary (10) and backup (20) mail servers. Google Workspace typically uses priorities 1, 5, 5, 10, 10 for load distribution and redundancy.

Email Provider Detection

Our tool automatically identifies your email provider by analyzing MX hostnames. Google Workspace uses aspmx.l.google.com, Microsoft 365 uses -com.mail.protection.outlook.com, and Zoho uses mx.zoho.com. This helps verify correct email configuration after provider migrations.

Common MX Issues

No MX Records: If no MX records exist, email delivery attempts fall back to A records pointing to the domain itself. This is not recommended—always configure explicit MX records for reliable email delivery.

Wrong Priority Values: Misconfigured priorities can route traffic to backup servers unnecessarily, degrading performance. Ensure your primary mail server has the lowest priority number.

Stale Records After Migration: After switching email providers, old MX records must be removed. Leaving obsolete records can cause intermittent delivery failures as some senders route to defunct servers.

FAQ

What is an MX record?▸
MX (Mail Exchange) records specify which mail servers handle email for your domain. Each record includes a priority number and mail server hostname. Lower priority numbers are tried first for email delivery.
How many MX records should I have?▸
Most domains have 2-5 MX records for redundancy. Google Workspace typically uses 5 MX records, while Microsoft 365 uses 1-2. Having multiple records ensures email delivery continues if one server becomes unavailable.
Why is email not being delivered to my domain?▸
Check if MX records exist and point to active mail servers. Verify SPF records authorize your mail servers. Ensure MX hostnames resolve to valid IP addresses. Check DNS propagation if you recently changed records.
What is MX priority?▸
MX priority (also called preference) is a number that determines mail server order. Sending servers try the lowest priority first. If delivery fails, they try progressively higher priorities. Common values are 10 (primary) and 20 (backup).
How long does it take for MX changes to propagate?▸
MX record changes typically propagate within minutes to hours, depending on TTL values. Lower your TTL to 300 seconds before making changes, wait for the old TTL to expire, then update records. Full global propagation usually completes within 24 hours.
Can I use MX records for subdomains?▸
Yes, each subdomain can have its own MX records. For example, [email protected] uses MX records configured for sub.example.com, which can differ from example.com. This enables different mail routing for different purposes.