Spammers using sender authentication too, study says
Sender ID is a technology standard that closes loopholes in the current system for sending and receiving e-mail that allow senders -- including spammers -- to fake, or "spoof," a message's origin. Organizations publish a list of their approved e-mail servers in the DNS (domain name system). That record, referred to as the sender policy framework (SPF) record, is then used to verify the sender of e-mail messages sent to other Internet domains using Sender ID.
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