Identify which email hosting provider or security gateway handles a domain's mail by matching MX record hostnames. This table covers 40+ email providers and security services including Google Workspace, Microsoft 365, Proofpoint, Mimecast, Barracuda, Cisco IronPort, and more. Useful for email deliverability troubleshooting, phishing investigation, vendor identification, and understanding an organization's email infrastructure.
| Fingerprint (MX) | Provider | Notes / Examples |
|---|
dig MX domain to identify mail flow and security gateways.
An MX (Mail Exchanger) record is a DNS record that specifies which mail servers accept email for a domain. When someone sends email to user@example.com, the sender's mail server queries the MX records for example.com to find where to deliver the message. MX records include a priority value — lower numbers have higher priority, creating failover chains for redundancy.
An email security gateway (also called a Secure Email Gateway or SEG) sits in front of a mail server and filters inbound email for spam, phishing, malware, and other threats. Services like Proofpoint, Mimecast, and Barracuda appear as MX records because all email must route through them first. You can identify these gateways by their MX hostnames — for example, *.pphosted.com indicates Proofpoint.
Use dig MX example.com on Linux/macOS or nslookup -type=MX example.com on Windows. The output shows the mail exchange hostnames and their priorities. Paste the hostname into the search above to identify the email provider. Our Domain Inspector tool also retrieves MX records automatically alongside WHOIS, NS, and other DNS data.