Major e-mail providers, including Google, Microsoft, and Yahoo! are teaming up with PayPal, Facebook, LinkedIn, and more, to implement a new system for authenticating e-mail senders to try to prevent the sending of fradulent spam and phishing messages. The protocol that powers e-mail, SMTP, dates back to a more trusting era; a time when the only people who sent you e-mails were people you wanted to send you e-mails. SMTP servers are willing to accept pretty much any e-mail destined for a mailbox they know about (which is, admittedly, an improvement on how things used to be, when they’d accept e-mails even for mailboxes they didn’t know about ), a fact which spammers and phishers exploit daily.

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Google, Microsoft, Yahoo!, PayPal go after phishers with new e-mail authentication effort