Rahul Sharma (Editor)

Composite Blocking List

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In computer networking, the Composite Blocking List (CBL) is a DNS-based Blackhole List of suspected E-mail spam sending computer infections.

The CBL takes its source data from very large spamtraps/mail infrastructures, and only lists IPs exhibiting characteristics such as:

  • Open proxies of various sorts (HTTP, socks, AnalogX, wingate etc.)
  • Worms/viruses/botnets that do their own direct mail transmission, or are otherwise participating in a botnet.
  • Trojan horse or "stealth" spamware.

    • The CBL attempts to avoid listing real mail servers, but certain misconfigurations of mail servers can make the system appear infected (for example, servers that send HELO with 'localhost' or a similar incorrect domain.)

    Entries automatically expire after a period of time.

    The CBL does not provide public access to gathered evidence.

    CBL data are used in Spamhaus XBL list.

    References

    Composite Blocking List Wikipedia
    (Text) CC BY-SA


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