The present generation "domain plus IP" email reputation query / response SIQ protocol has been in use in production mail servers since July 2003. This succinct slide presentation was made at the ASRG "Identity, Authentication and Reputation" session of the 61st IETF meeting held in Washington DC November 2004.

The SIQ protocol has MTA query clients available for sendmail, postfix and exchange, plus command line query clients for *nix and win.
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