5.7.1 Error on SMTP messages

Posted on 2006-03-22
Last Modified: 2008-01-09
I'm getting some messages bounced back from a few recipients.  Here is what the receipt says:

 There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
            < #5.5.0 smtp;553 sorry, that domain isn't in my list of allowed rcpthosts (#5.7.1)>

I recently added a PTR record to my mail server because email to AOL and Optimum Online were being delayed and bounced.

When I go to DNS reports, everything passes but i get a warning that I think might be related to this issue.  It reads:

WARNING: One or more of your mail servers is claiming to be a host other than what it really is (the SMTP greeting should be a 3-digit code, followed by a space or a dash, then the host name). This probably won't cause any harm, but is a technical violation of RFC821 4.3 (and RFC2821 4.3.1). Note that the hostname given in the SMTP greeting should have an A record pointing back to the same server. claims to be invalid hostname '*******************************************************************
   220 ***************************************************************

Here is the background information:

I'm running MS Exchange Server 2003 which is also the domain controller running AD.
The external domain is: but the internal domain name is:
The internal name of the server is:

The MX record points to an external IP address as

My SMTP virtual server has the masquerade domain and the FQDN as

Any help or assistance is greatly appreciated in advance.
Question by:cgizzi
    LVL 104

    Accepted Solution

    You have a PIX.
    Disable the Fixup SMTP option in the Pix and that will stop a lot of the problems.

    Once you have got that changed, make sure that your server is announcing itself correctly, and that the reverse DNS matches what the server announces itself as.


    Author Comment

    Well, I do have the server behind a PIX Firewall but I don't think Fixup on SMTP is enabled.  I don't see that line when I show the config.

    but I did turn off esmtp inspection just in case they are the same thing.

    And on the second suggestion, the DNS lookup works... and I know that its set to the right value of

    Hopefully, your first suggestion works.

    LVL 104

    Expert Comment

       220 ***************************************************************

    Is classic PIX with fixup SMTP.
    If you have a PIX with version 7.0 of the software it might be called something else. I haven't seen a 7.0 PIX yet so cannot be sure what they changed.


    Write Comment

    Please enter a first name

    Please enter a last name

    We will never share this with anyone.

    Featured Post

    Hire Top Freelancers to Complete Exchange Projects

    Source the talented Expert Exchange community
    for top quality work on your Exchange projects.

    Hire the best. Collaborate easily. Get quality work.

    In this video we show how to create a User Mailbox in Exchange 2013. We show this process by using the Exchange Admin Center. Log into Exchange Admin Center.: First we need to log into the Exchange Admin Center. Navigate to the Recipients >> Mailb…
    To add imagery to an HTML email signature, you have two options available to you. You can either add a logo/image by embedding it directly into the signature or hosting it externally and linking to it. The vast majority of email clients display l…

    759 members asked questions and received personalized solutions in the past 7 days.

    Join the community of 500,000 technology professionals and ask your questions.

    Join & Ask a Question

    Need Help in Real-Time?

    Connect with top rated Experts

    11 Experts available now in Live!

    Get 1:1 Help Now