Reverse MX Lookup | Whois XML API

Instantly check which domains are hosted on a mail server with Reverse MX Lookup

Reverse MX Lookup gives you a list of all domains hosted on a mail server of interest in seconds. Use this information for cybersecurity, optimizing email operations, and more.

Reverse MX Lookup
1,473,142,430Domains and subdomains
142,703,533MX records updated daily
2,131Satisfied customers

Why Reverse MX Lookup?

  • Backed by Billions of Domains and Subdomains

    Our reverse MX lookup tool has access to a comprehensive database that contains information on close to 1.5 billion domains and subdomains and 150 million MX records updated daily.

  • Readily Available Reverse MX Results

    Each lookup reveals the number of MX records related to the mail server of interest and provides a list of all the domains connected to it, along with details on when their MX records were last updated.

Practical usage

Check for Bad Actors on Mail Servers

Check for Bad Actors on Mail Servers

Sharing a mail server with a malicious domain can be detrimental to your organization’s reputation and can very well cause your domain’s inclusion in a blacklist. Use Reverse MX Lookup to get a list of all your mail server co-occupants so you can do thorough background checks on them. Make sure none of them are known spammers, phishers, or malware hosts.

Review MX DNS Infrastructure

Cybercriminals sometimes get into target networks undetected by taking control of so-called “dangling records.” These can include MX records for subdomains that are left unprotected because they are no longer in use. Use Reverse MX Lookup to keep track of domains and subdomains that may have slipped into the cracks.

Review MX DNS Infrastructure
Safeguard Email Deliverability

Safeguard Email Deliverability

Being associated to a malicious mail server can result in email deliverability drops and hit your bottom line. Reverse MX Lookup can let you know about all new domains added to a mail server so you can identify and take further actions against bad online neighbors.

DNS Database Download

Enrich mail server data with comprehensive DNS database downloads

Our passive DNS database downloads are available in CSV and MySQL files with all connections between IP addresses, domains, and sub-domains since 2008.

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