How can i prevent 521-EHLO/HELO from sender error

Posted on 2006-06-07
Last Modified: 2010-03-06
Ok here is the issue.

We have an older backend exchange (RISERVER01) server with a front end. Recently we added a 2nd backend server to the mix. The mail addresses are the same...we just moved the mailbox because some of the users were in a different location.  Again the mail addresses remained the same. The problem is that the users that we moved have gotten a few returns from comcast.

 < #5.5.0 smtp;521-EHLO/HELO from sender does not map to in DNS>

We only have one public dns entry and it points to the old server RISERVER01.  I tried changing FQDN on the new server to match the one on the existing server...but the issue remains. I understand why but what would be the best solution to fix this issue?  Can i have our ISP map two DNS entries to Only comcast address appear to be having issue with this...but is there a way to fix and have it announce itself as RISERVER01 even though it is RISERVER02? Otherwise the email is working fine...this is the only issue. Any help would be greatly appreciated.  I changed the name of the servers but they still illustrate the problem.  Is there a setting i can modify in exchange?

Question by:riuser
    LVL 9

    Expert Comment

    If your public IP is that is being seen by comast, then it does not appear to have a reverse PTR entry.

    Create PTR to point to the server name that would send the email to internet.

    I am sure if the above theory is right you will not be able to send emailt o AOL.COM also.

    LVL 104

    Accepted Solution

    Two things I would do.

    1. Get the reverse DNS setup correctly, and point it at the frontend server.
    2. Setup an SMTP Connector. Configure it to use DNS. Configure the SMTP VS on your frontend server ONLY as the bridgehead. As long as all the servers are in the same routing group, all outbound email will go out through the frontend server.


    Author Comment

    so..if i already have a have one backend server pointed @ the frontend server can i add a second to also point to the frontend server?  I did notice they are not in the same routing group...going to find out why before i change.
    LVL 104

    Expert Comment

    That sounds like you don't have your SMTP Connector configured correctly.
    Have you tried to use the frontend server as a smart host?


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