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Untangle Network Security by Abd El-Monem A. El-Bawab

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Spam!!…It's something from the past

Spam consists of identical messages that are sent to numerous recipients by e-mail (that is unsolicited bulk e-mail). Spam e-mails may contain commercial advertisements or links to dangerous sites (that is phishing sites, or sites that include malware).

How anti-spam programs work

Anti-spam programs run many tests against the message, and each test will have a score based on the message criteria. The overall score determines if the message is a spam message or not. The different tests include:

  • DNS Black Listing (DNSBL): This contains bad-behavior IPs that were automatically collected using spam detection tools or manually reported. A famous example of a blacklist provider is Spamhaus.
  • Heuristic/Signature-based content ...

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