title: Specify the "send via"- or "on behalf of"-value in Mandrill
body: <p>I'm using Mandrill to send E-Mails in my PHP Project and integrated it via the API. So far so good E-Mails go out and arrive their recipient, but something bothers me about the missing SPF and DKIM entries.</p>
  
  <p>When the E-Mails are opened in outlook the "on behalf of" issue  occurs (<a href="https://mandrill.zendesk.com/hc/en-us/articles/205582237-How-do-I-get-rid-of-the-on-behalf-of-message-that-shows-for-some-recipients-" rel="nofollow">FAQ from mandrills KB</a>). But I can't fix this, since too many of our customers do not have the necessary skills/ access-rights to create a SPF entry for their domain, so we learned to live with that.</p>
  
  <p>We verified our own domain at mandrill to use it as <a href="https://mandrill.zendesk.com/hc/en-us/articles/205582387-How-do-I-set-up-sending-domains-" rel="nofollow">custom sending-domain</a> to get rid of the</p>
  
  <pre><code>from: reallyLongString@mandrillapp.com on behalf of customerName@customerDomain.com
  </code></pre>
  
  <p>and exchange it with</p>
  
  <pre><code>from: mailbot@ourDomain.com on behalf of customerName@customerDomain.com
  </code></pre>
  
  <p>but somehow I can't get this to work!</p>
  
  <p>I cannot find an option to set "mailbot" as sender. Even worse, Mandrill makes up a phantasy e-mail-address consisting of <strong>customerName@ourDomain.com</strong>. If some customer gets the idea to send to this address we've got a disaster upcoming. Also the API does not specify anything like that in the "Messages"-Section.</p>
  
  <p>How can I configure mandrill to send E-Mails with a from-field appearing in outlook like this:</p>
  
  <pre><code>mailbot@ourDomain.com on behalf of customerName@customerDomain.com
  </code></pre>
  
  <p>? Really cannot find anything in the docs or the web. Thanks in advance!</p>