Microsoft Exchange will transform the message, for example, adding angle brackets around From: addresses, adding quote marks around parts of the Content-Type header, etc. This will break DKIM verification. If you install a 3rd party signing agent and use Exchange as your outbound MTA, then it will not break DKIM (since it will reformat and then sign the message, and then at the receiving MTA which doesn't modify content, it will verify just fine).
We are fixing this behavior in Exchange in the Office 365 service and then in a future release will push this down onto on-premise deployments via Microsoft Update (we have no timelines around this). We will probably do this for Exchange 14 and E15, but most likely not previous versions. -- Terry -----Original Message----- From: dmarc-discuss [mailto:[email protected]] On Behalf Of Michael Storz Sent: Wednesday, April 30, 2014 12:51 AM To: Dmarc Discuss Subject: [dmarc-discuss] Novell GroupWise and DKIM Looking into my logs, it seems that not only Microsoft Exchange but Novell GroupWise too is destroying DKIM signatures. Can someone confirm this or has more information? About Lotus Domino Server, I haven't made up my mind. I have only one example of a destroyed signature where the email looks like it was routed through a Lotus Domino Server and no example of a survived signature. -- Michael _______________________________________________ dmarc-discuss mailing list [email protected] http://www.dmarc.org/mailman/listinfo/dmarc-discuss NOTE: Participating in this list means you agree to the DMARC Note Well terms (http://www.dmarc.org/note_well.html) _______________________________________________ dmarc-discuss mailing list [email protected] http://www.dmarc.org/mailman/listinfo/dmarc-discuss NOTE: Participating in this list means you agree to the DMARC Note Well terms (http://www.dmarc.org/note_well.html)
