Hi On Thu, May 27, 2021 at 02:33:10PM -0500, Chris Adams via mailop wrote: > Emails leaving our platform have a proper From header. However, when they > are received by Carrierzone, both the From and Return-Path headers have had > the domain replaced with "sparkpostmail.com". It's almost as if they are > using the organizational domain from our connecting IP's rDNS lookup and > rewriting the header using that domain.
It's actually a lot easier. They are following a CNAME: | ;; ANSWER SECTION: | send.osdealerfuel.com. 300 IN CNAME sparkpostmail.com. AFAIK only Sendmail ever exhibited this property of rewriting From header due to CNAME. > Authentication-Results-Original: mail314c28.carrierzone.com; dkim=pass > (1024-bit key) header.d=send.o*******l.com <http://send.osdealerfuel.com/> > [email protected]***********l.com <[email protected]> > header.b="tBmppuh8" Is there a reason why you break the example headers you send? There are not supposed to be any "*" or "<>" in there. And they are rewrapped, kind off. > Received: from mta-88-193.sparkpostmail.com (mta-88-193.sparkpostmail.com > [192.174.88.193]) > by mail314c28.carrierzone.com (8.14.9/8.13.1) with ESMTP id 14MEd3NK026470 Sure, Sendmail. Bastian -- Klingon phaser attack from front!!!!! 100% Damage to life support!!!! _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop
