12 References and Links

• Greylisting - The Next Step in the Spam Control War

  http://projects.puremagic.com/greylisting/. In 2003 Evan Harris came up with the idea of greylisting. This is his site describing the method.

• Greylisting article on Wikipedia

  http://en.wikipedia.org/wiki/Greylisting. This page describes greylisting in general.

• Postgrey

  http://postgrey.schweikert.ch/. dgrey is based on Postgrey by David Schweikert.

• Postfix SMTP Access Policy Delegation

  http://www.postfix.org/SMTPD_POLICY_README.html. This page describes the protocol between the mail server and dgrey.

• Greylisting in Distributed Checksum Clearinghouse

  http://www.rhyolite.com/anti-spam/dcc/greylist.html. Another daemon capable of synchronizing greylisting information between servers?

XXX Here should be more references.