The document discusses spam and various anti-spam technologies, describing what spam is, its negative effects, and how it is a difficult problem to solve given human and technical factors. It outlines the messaging infrastructure and email format, and then explains different anti-spam techniques including blocklists, greylisting, content filtering, challenge-response, and sender-driven methods. Finally, it covers how spammers attempt to evade these filters and techniques through techniques like exploiting open relays, sending through free webmail, and targeting low priority mail exchangers.

1. AntiSpam Understanding the good, the bad and the ugly By Aseem Jakhar Confidential

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