MX (Mail Exchange) records tell the internet where to deliver email for a domain. Each MX record points to a server that handles incoming email, and many of these server names can reveal the hosting provider. If you know how to read them, you can figure out who’s running the mail system.

Why you might need to identify an email host from MX records

• Troubleshooting email delivery issues: Find the right provider to contact when emails bounce or get delayed.
• Migrating to a new email service: Update MX records to switch email hosting.
• Pointing your website to a new hosting without moving your domain or email from current provider: Updating only the necessary DNS records and retaining the MX records
• Auditing or securing a domain: Confirm mail is routed through trusted servers.
• Investigating spoofing or phishing: Verify if messages are truly from the claimed domain.
• Competitive research or IT tracking: Identify what services other companies are using.

How to check MX records

1. Online lookup tools: Use MXToolbox and enter the domain name.
2. Command line:
   • Windows: nslookup -type=mx example.com
   • macOS/Linux: dig mx example.com
3. Note the hostnames: Each MX record shows a priority and a server address.

How to interpret MX record results

• Exact matches: Match the hostname against known provider patterns.
• Generic hostnames: Use reverse IP lookup if it’s something like mail.example.com.
• Third-party filters: Some MX records point to spam filters like Proofpoint or Barracuda.

MX record identification cheat sheet

Tips for confirming the provider

Check also other DNS and Zone records by using other DNS checker tools like https://dnschecker.org/ which can help you verify other ownership and DNS records in relation to your webmail and hosting in general.

• Run reverse DNS lookups on the MX hostnames.
• Check WHOIS for the IP to see the ASN owner.
• Look at SPF/DKIM records for provider clues.
• Watch for spam filter intermediaries.