Mail servers, SPF & DMARC for any domain
MX (Mail Exchange) records are DNS records that specify which mail servers are responsible for receiving email on behalf of a domain. When someone sends an email to user@example.com, the sending mail server performs a DNS query for the MX records of example.com, then connects to the specified mail server to deliver the message. Without properly configured MX records, a domain cannot receive email.
Beyond MX records, email deliverability depends on several other DNS-based authentication mechanisms. SPF (Sender Policy Framework) records define which servers are authorized to send email for your domain. DMARC (Domain-based Message Authentication, Reporting and Conformance) records tell receiving servers how to handle messages that fail SPF or DKIM checks. This tool checks all of these components together, giving you a complete picture of your domain's email configuration.
To use this tool, enter any domain name and it will retrieve the MX records, SPF policy, DMARC configuration, and name server details. The results help you verify that your email infrastructure is correctly configured, diagnose delivery problems, and ensure your domain has the proper authentication records to avoid being flagged as spam.
MX records are DNS entries that tell the internet where to deliver email for your domain. Each MX record points to a mail server hostname and includes a priority number. Without MX records, email sent to your domain will bounce back to the sender with a delivery failure. Even if you use a third-party email provider like Google Workspace or Microsoft 365, you still need MX records pointing to their mail servers.
The priority value (also called preference) determines the order in which mail servers are tried. Lower numbers indicate higher priority. For example, a server with priority 10 will be tried before one with priority 20. If the highest-priority server is unavailable, the sending server falls back to the next one in order. This system provides redundancy so email delivery continues even if one mail server goes down.
Yes, and most properly configured domains do. Having multiple MX records provides redundancy and load balancing. Email providers like Google Workspace typically use five MX records with different priorities. If the primary server is unreachable, the sending server automatically tries the backup servers in priority order. You can also have multiple MX records with the same priority, in which case sending servers distribute mail across them randomly.
Start by checking that your MX records point to the correct mail servers for your email provider. Verify that your SPF record includes all servers that send email on your behalf -- a missing SPF entry is a common cause of emails landing in spam. Check that your DMARC record exists and has a valid policy. If any of these records are missing or misconfigured, the tool will help you identify exactly what needs to be fixed.
If no MX records exist for a domain, sending mail servers will fall back to the domain's A record (the IP address the domain points to) and attempt to deliver email directly to that server on port 25. In practice, this rarely works because most web servers are not configured to accept email. The result is usually a bounced message with an error like "no MX record found" or "mail delivery failed." To receive email reliably, you must have valid MX records configured.
