Posted on 2011-10-18
Last Modified: 2013-12-17
I have an internal RHEL server called gospel on domain cotw. This is on a Windows network w/ an Exchange server (  I need to get application generated emails from my RHEL box to masquerade as coming from my exchange box.
I have attempted the following changes to my sendmail

My resultant email still reflects what's shown below.  Some headers are changed but not the important ones regarding RDNS.  What else can I try?
Microsoft Mail Internet Headers Version 2.0
Received: from mail pickup service by with Microsoft SMTPSVC;
       Tue, 18 Oct 2011 13:55:19 -0400
X-SCL: 5 67.76%
Received: from gospel.cotw.local ([] RDNS failed) by with Microsoft SMTPSVC(6.0.3790.4675);
       Tue, 18 Oct 2011 13:55:09 -0400
Received: from gospel.cotw.local (localhost.localdomain [])
      by gospel.cotw.local (8.13.8/8.13.8) with ESMTP id p9IHt8YA017253
      for <>; Tue, 18 Oct 2011 13:55:08 -0400
Received: (from randy@localhost)
      by gospel.cotw.local (8.13.8/8.13.8/Submit) id p9IHt8sv017252
     for; Tue, 18 Oct 2011 13:55:08 -0400
Date: Tue, 18 Oct 2011 13:55:08 -0400
From: Randy Huseland <>
Message-Id: <201110181755.p9IHt8sv017252@gospel.cotw.local>
Subject: testing
X-OriginalArrivalTime: 18 Oct 2011 17:55:09.0315 (UTC) FILETIME=[138C8D30:01CC8DBF]

Question by:rhuseland
    LVL 76

    Expert Comment

    The only people who would know the path the mail took are those who look at the message headers.

    The masquerade deals with altering visible content From: etc.


    Author Comment

    Yea but the problem is Received: from gospel.cotw.local ([] RDNS failed
    I need to make gospel.cotw.local turn into so RDNS will pass.
    LVL 76

    Expert Comment

    Did you update the configuration after adding the parameters as outlined in the link I posted?

    Provided the From: and/or Reply-To: address would direct the response to the correct location, I've not seen a reason to do this setup.  At times it could make it harder to troubleshoot/isolate the source of an email even though an individual receiving an email from each source will clearly see the difference i.e. one will have many more Received Lines.
    LVL 76

    Accepted Solution

    Oh, the Masquerade occurs prior to the message being submitted to the Exchange which is the source of the Received header you referenced.  Nothing on the sendmail side can be done to handle this.
    You would have to update the RDNS for the IP in question to reflect a different hostname.

    Author Comment

    Hmmm. Not the answer I was looking for. Maybe I'll have to look for another solution.
    LVL 76

    Expert Comment

    What is the significance that you are going through all this.
    Does your exchange server also has IIS for OWA?
    You could have your process submit email via IIS to an ASP/ASP.NET page that will generate the email. i.e. submit the data as a form.
    Alternatively, you could use masquerade as you have, but send the message directly versus routing it through the exchange. This way the receiving server will not be able to differentiate whether the sender is the exchange or not, but the headers will clearly have sendmail as the sending app versus an MS SMTP service.

    Assisted Solution

    Basically "fixed" it by forcing a change to my Received header in my
    LVL 15

    Expert Comment

    This question has been classified as abandoned and is closed as part of the Cleanup Program. See the recommendation for more details.

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