= Strict DMARC strategy = Yahoo is asking email providers to use strict alignment when evaluating DMARC policies for email messages claiming to be from Yahoo (see [wiki:dmarc-and-mailing-lists our general FAQ for more information]. This page describes our technical approach to addressing this problem. Our mailing list software relays ''all'' mail to dedicated email relay machines (see [wiki:bulk-mail-relay our bulk mail relay] page for details on how that system operates. Through our [wiki:puppet puppet configuration] (modules/mayfirst/manifests/postfix.pp), our bulk mail relay machines use [http://www.postfix.org/header_checks.5.html Postfix header checks] to replace the From: line from any email message that is from a yahoo account to a custom address. Here's the regular expression: {{{ /From: (.*?)/ REPLACE From: "$1 (Relayed)" }}} The custom address has an auto-responder that refers people to our [wiki:dmarc-and-mailing-lists general FAQ] on this topic.