Gmail shows "via" even if the domain is authenticated with Mailchimp and has valid SPF and DKIM records

Question

I'm sending a newsletter with Mailchimp and Gmail shows that the mail is sent via mail5.mcsignup.com even though I added Mailchimp's SPF and DKIM records and the domain is authenticated in Mailchimp.

Outlook also shows that the email is sent "on behalf of".

I have tested the SPF with mxtoolbox.com and the DKIM with dkimcore.org and they are valid.

It also looks that the SPF and DKIM pass in the gmail header. Below is the header from Gmail:

   *ARC-Authentication-Results: i=1; mx.google.com;
           dkim=pass header.i=@mail5.mcsignup.com header.b=G93ARUrl;
           dkim=pass header.i=@mandrillapp.com header.b=i0uux1aP;
          spf=pass (google.com: domain of bounce-md_9656357.596bc38e.v1-
    43028f7e330f4128b36015188bc1fb10@mandrillapp.com designates 205.201.136.19 as 
    permitted sender) smtp.mailfrom=bounce-md_9656357.596bc38e.v1-
    43028f7e330f4128b36015188bc1fb10@mandrillapp.com
    Return-Path: <bounce-md_9656357.596bc38e.v1-
    43028f7e330f4128b36015188bc1fb10@mandrillapp.com>
    Received: from mail5.mcsignup.com (mail5.mcsignup.com. [205.201.136.19])
            by mx.google.com with ESMTPS id 
   d10si3015324yba.575.2017.07.16.12.50.38
            for <EMAIL@gmail.com>
            (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);
           Sun, 16 Jul 2017 12:50:38 -0700 (PDT)
    Received-SPF: pass (google.com: domain of bounce-md_9656357.596bc38e.v1-
    43028f7e330f4128b36015188bc1fb10@mandrillapp.com designates 205.201.136.19 as 
    permitted sender) client-ip=205.201.136.19;
    Authentication-Results: mx.google.com;
           dkim=pass header.i=@mail5.mcsignup.com header.b=G93ARUrl;
           dkim=pass header.i=@mandrillapp.com header.b=i0uux1aP;
           spf=pass (google.com: domain of bounce-md_9656357.596bc38e.v1-
    43028f7e330f4128b36015188bc1fb10@mandrillapp.com designates 205.201.136.19 as 
    permitted sender) smtp.mailfrom=bounce-md_9656357.596bc38e.v1-        
    43028f7e330f4128b36015188bc1fb10@mandrillapp.com
    DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; s=mandrill; 
    d=mail5.mcsignup.com; h=From:Sender:Subject:To:Message-Id:Date:MIME-
    Version:Content-Type; i=contact@mail5.mcsignup.com; 
    bh=fnyV42cJxlWmSMb63R6R/rVuLTzDaUFDaGqL0N4WaMA=; 
   b=G93ARUrloP6yy40uMAHkv9TNXH/7GDjg4ozK0rk7oeKQ40lWaWzkB8UTgsMyHTSNLNneWdcTWlCO       
     INNBCc55gqlISw08WRn52e+7gQWx8vllJv77RiJiX58wFJYsTbrLQA086QQ/8EYEKo9Mtgqzxg4/
       2CFWJPCv3XKRgg6Nnmg=
    Received: from pmta07.mandrill.prod.suw01.rsglab.com (127.0.0.1) by 
    mail5.mcsignup.com id hdf1os174e0q for <EMAIL@gmail.com>; Sun, 16 Jul 2017 
    19:50:38 +0000 (envelope-from <bounce-md_9656357.596bc38e.v1-
    43028f7e330f4128b36015188bc1fb10@mandrillapp.com>)
    DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mandrillapp.com;
      i=@mandrillapp.com; q=dns/txt; s=mandrill; t=1500234638; h=From :
      Sender : Subject : To : Message-Id : Date : MIME-Version : Content-Type
      : From : Subject : Date : X-Mandrill-User : List-Unsubscribe;
      bh=fnyV42cJxlWmSMb63R6R/rVuLTzDaUFDaGqL0N4WaMA=;
      b=i0uux1aPb7yxSqpYdr5e45hKJHeAb1ow5k4xE9K7/NxlKt4JW9xvSS3AazIojjleDpLqfC 
    4gESZATfoj6eAXRSqoq2+o6Jxfwi7tvEdTf4IjdonTl3QioXSHJj/joagC8nKJ3HQIaPIh+I 
    xycoNL7i/nXzcQqlslsYW9z1G+/Hs=
    From: MY COMPANY <contact@mydomain.com>
    Sender: MY COMPANY <contact@mail5.mcsignup.com>
    Subject: MY SUBJECT
    Return-Path: <bounce-md_9656357.596bc38e.v1-
    43028f7e330f4128b36015188bc1fb10@mandrillapp.com>
    X-Accounttype: ff
    X-Auto-Response-Suppress: OOF, AutoReply
    Auto-Submitted: auto-generated
    Form-Sub: v=1;ip4=MY IP
    To: "EMAIL@gmail.com" <EMAIL@gmail.com>
    X-Report-Abuse: Please forward a copy of this message, including all headers, 
    to abuse@mandrill.com
    X-Report-Abuse: You can also report abuse here: 
     http://mandrillapp.com/contact/abuse?
    id=9656357.43028f7e330f4128b36015188bc1fb10
    X-Mandrill-User: md_9656357
    Message-Id: 
    <9656357.20170716195038.596bc38e18bbf4.75410701@mail5.mcsignup.com>
    Date: Sun, 16 Jul 2017 19:50:38 +0000
    MIME-Version: 1.0*

I am also using cloudflare on that domain.

Am I missing something? Any suggestions on how to remove the "via" and "on behalf of"?

score 1 · Answer 1 · answered Jun 05 '18 at 02:28

This is why Outlook says "On behalf of":

From: MY COMPANY <contact@mydomain.com>
Sender: MY COMPANY <contact@mail5.mcsignup.com>

If there is a Sender header as well as a From header, then this indicates a 'Secretary scenario' where the massages was sent by one account (usually a mailing list, but originally a secretary) but is actually From another (such as the company CEO, who doesn't know how to use email...)

When Outlook sees a Sender header, it displays this as From $from on behalf of $sender

Mailing lists will usually set a Sender header, and in fact are supposed to according to the RFC, so that security systems such as SIDF can validate against Sender rather than against From (although DMARC doesn't do this, which is another issue).

score 0 · Answer 2 · answered Sep 29 '20 at 09:25

While sending an email there are multiple domains included.

HEADER FROM is a domain that you see after the username (in abc@example.com, example.com is HEADER FROM Domain)
MAIL FROM is a domain that is used for sending an email. Which you will see in the Header Section under Return-Path. In the header, you mentioned the MAIL FROM domain is mandrillapp.com

So basically while sending email your email service provider is using mandrillapp.com as your sending domain. To fix this all you have to do is just change the return path with your domain. You can use any subdomain from your domain that doesn't matter. You can still use root domain in HEADER FROM.

Follow this article to make the changes. https://mandrill.zendesk.com/hc/en-us/articles/360039293113-How-to-Customize-the-Return-Path-Address

Gmail shows "via" even if the domain is authenticated with Mailchimp and has valid SPF and DKIM records

2 Answers2