BTCBlack - Blocklist Threat Clearinghouse — Real-time DNS Blacklists

Freemail Accounts RBL

freemail.btcblack.it

Free webmail services - Gmail, Yahoo Mail, Outlook.com, and hundreds of others - are a common source of spam and phishing campaigns. Their low barrier to account creation, combined with the implicit trust many mail systems place in large providers, makes them an attractive vehicle for abuse that slips past conventional reputation filters.

This DNSBL lists hashed freemail addresses confirmed as sources of spam, phishing, or other abusive messages. It allows mail filters to apply additional scrutiny to messages sent from or referencing known-abusive freemail accounts without blocking entire provider domains.

Key Features

• Surgical blocking: Targets individual abusive accounts rather than blacklisting entire freemail domains.
• Privacy-preserving: Addresses are stored as cryptographic hashes — the original address is never exposed.
• SpamAssassin integration: Queryable via the HashBL plugin against From, Reply-To, and Envelope-From headers, included on KAM.cf ruleset.

Supported Providers

Any freemail domain can be listed; providers with the highest volume of tracked abusive accounts currently include Gmail, Yahoo Mail, Outlook.com, Hotmail, and GMX. Because blocking operates at the individual account level rather than the domain level, legitimate users on the same provider are entirely unaffected.

Listing Policy

Addresses are listed only when confirmed as a source of spam or phishing through spam trap data or validated abuse reports. To request removal of a mistakenly listed address, provide evidence of legitimate use to info@btcblack.it.

DNS Query Example

$ host <md5-of-address>.freemail.btcblack.it
Using domain server:
Name: 8.8.8.8
Address: 8.8.8.8#53
Aliases:

<md5-of-address>.freemail.btcblack.it has address 127.0.0.2

Check if a Freemail address is blacklisted:

For more info send an email to info@btcblack.it.
The service is sponsored by SNB.