Email intelligence

MX Record

A DNS record that specifies the mail server responsible for receiving email on behalf of a domain.

Tomba Team
March 23, 2026

An MX (Mail Exchange) record is a type of DNS record that directs email to the correct mail server for a given domain. When someone sends an email to an address at your domain, the sending server looks up your MX records to determine which server should receive the message. Without properly configured MX records, a domain cannot receive email at all.

In B2B prospecting and sales, understanding MX records provides valuable intelligence. By examining a company's MX records, you can determine which email provider they use (Google Workspace, Microsoft 365, etc.), which can inform your outreach strategy and help you understand their technical infrastructure.

MX records also play a role in email verification. If no MX records exist or they point to inactive servers, any email sent to that domain will bounce.

Key Points

  • Directs incoming email to the correct mail server for a domain
  • Reveals which email provider a company uses (useful for prospecting intelligence)
  • Essential for email verification, as domains without MX records cannot receive mail

How It Works

MX records are published in a domain's DNS zone and contain a priority value and a mail server hostname. When an email is sent, the sending server queries the recipient domain's MX records, then delivers the email to the server with the highest priority (lowest number). Multiple MX records can be configured for redundancy.

Best Practices

  • Set up at least two MX records for redundancy in case one server goes down
  • Use MX record lookups as part of your prospecting research to understand target companies

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