MX Record Checker

MX (Mail Exchange) records are DNS records that specify which mail servers are responsible for receiving email for a domain. When someone sends an email to your domain, the sending server looks up your MX records to determine where to deliver the message.

How MX Priority Works

Each MX record has a priority (preference) number. Lower numbers indicate higher priority. The sending server will try the highest-priority (lowest number) server first. If that server is unavailable, it falls back to servers with higher numbers.

Example MX Records

example.com.  MX  10  mail1.example.com.
example.com.  MX  20  mail2.example.com.
example.com.  MX  30  mail3.example.com.

Best Practices

• Redundancy — Always have at least two MX records pointing to different servers for failover.
• A records — Each MX host must have a valid A record. MX records should point to hostnames, not IP addresses.
• No CNAME — MX records must not point to CNAME records per RFC 2181.
• Priority spacing — Use gaps between priority values (e.g., 10, 20, 30) to allow easy insertion of new servers.

MX and Email Authentication

MX records work alongside SPF, DKIM, and DMARC to ensure email deliverability and security. While MX records control where inbound email goes, SPF records control which servers can send outbound email on your behalf.