One of my client's received this NDA today when sending to
I was able to send an email to no problems from Gmail.
No other users have reported any issues sending mail.
Environment is SBS 2008 with Exchange 2007, Outlook 2007 client basically a default environment inregards to exchange which has been running for 1 year no problems. The user has no issue sending to other email address both internally or externally.

Customer name in all instance below has been directly replaced by abc and the customer's IP address has been changed all else remains the same.

Would be keen for somebody to give me any pointers here as im a bit stumped as to where the issue is.

PM/Contact me if you want the real Domain Details for investagation.


From: Mail Delivery Subsystem []
Sent: Tuesday, 23 August 2011 1:09 PM
To: Nicole Nowland
Subject: Undeliverable: Oldstream Pty Ltd
Delivery has failed to these recipients or distribution lists:
Microsoft Exchange couldn't deliver the message to this recipient because it didn't recognize you as a valid sender. Please verify that you have the correct sending address configured in your e-mail client and try sending your message again, or provide the following diagnostic text to your system administrator.
The following organization rejected your message:
Diagnostic information for administrators:
Generating server: #< #5.1.8 SMTP; 553 5.1.8 <>... Domain of sender address does not exist> #SMTP#
Original message headers:
Return-Path: <>
Received: from ( [])
        by (8.13.8/8.13.6) with ESMTP id p7N33L97017817
        for <>; Tue, 23 Aug 2011 13:03:21 +1000
Received: from ( [])
        by (8.13.8/8.13.6) with ESMTP id p7N33LES028988
        for <>; Tue, 23 Aug 2011 13:03:21 +1000
X-FW-MsgID: <08/23/>
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: Av8EAGcXU07L2RZ3/2dsb2JhbAArFoJNpVR4gUIFLSk1ASoJAksHHwEEG51DoFeDHhyCL18Ejh+Ed5EL
X-IronPort-AV: E=Sophos;i="4.68,267,1312120800";
Received: from (HELO ([])
  by with ESMTP; 23 Aug 2011 13:03:21 +1000
Received: from SERVER.abcsydney.local ([fe80::cfe6:349:7230:a064]) by
 SERVER.abcsydney.local ([fe80::cfe6:349:7230:a064%10]) with mapi; Tue, 23
 Aug 2011 13:03:36 +1000
From: Nicole Nowland <>
To: Danny May <>
Date: Tue, 23 Aug 2011 13:03:35 +1000
Subject: Oldstream Pty Ltd
Thread-Topic: Oldstream Pty Ltd
Thread-Index: AcxhQT/ddS3ynZ7zRU6JFSov9z7hIA==
Message-ID: <341AFBD3E2294F4C898D72F7C16F1C7E2C2E4FD9@SERVER.abcsydney.local>
Accept-Language: en-US, en-AU
Content-Language: en-US
acceptlanguage: en-US, en-AU
Content-Type: text/plain
MIME-Version: 1.0

asked 08/23/2011 05:58

it-pro's gravatar image

it-pro ♦♦

3 Answers:
Plase check the DNS domain of the sender.

5.1.8 SMTP; 553 5.1.8 <>... Domain of sender address does not exist> #SMTP#

means, that the remote server cannot resolve the domain "" by DNS.
Please check your MX and optionally A DNS records for "" if they are set correctly.
Or perhaps it's only a DNS caching issue, if you have recently added the zone/records for and they are not yet available.
ScRe's gravatar image


The receiving mail server I have confirmed could not resolve the Server for a short period of time..
All is good now
it-pro's gravatar image


DNS was the issue
it-pro's gravatar image


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Asked: 08/23/2011 05:58

Seen: 1198 times

Last updated: 09/05/2011 09:22