Declan McCullagh, writing in CNET, makes the standard schoolboy error of assuming that email sender authentication technologies are "antispam techniques."
They’re not.
DomainKeys Identified Mail (DKIM) and other sender authentication technologies are simply ways to detect forgeries. At best, they give a partial indication whether a message is spam or not, but their main use is to allow recipients to look up the reputation of the sending domain.

Read more at rcbarnett

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