HELP!!!! Emails arriving 24 hours after they were sent and in some cases, customers receiving ndr's.

Still pretty new to supporting email:

Two part question:

How do I find out why we are receiving some emails anywhere from 8 hours to 24 hours after they were sent?  I have a copy of one of the email headers below:

Microsoft Mail Internet Headers Version 2.0
Received:  from ( []) by with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2657.72) id XRPL9D93; Wed, 24 Nov 2004 20:51:27 -0600
Received:  from ([]) by with ESMTP  id KP-NTG56.37237762; Tue, 23 Nov 2004 08:46:09 -0600
content-class: urn:content-classes:message
Subject: Re: Mart Stores - Flighting
MIME-Version: 1.0
Content-Type: application/ms-tnef;
Date: Tue, 23 Nov 2004 08:37:15 -0600
Content-Transfer-Encoding: binary
Message-ID: <>
X-MS-Has-Attach: yes
X-MS-TNEF-Correlator: <>
X-MimeOLE: Produced By Microsoft Exchange V6.0.6603.0
Thread-Topic: Mart Stores - Flighting
Thread-Index: AcTSmaizTZj+up2qRGutMfe63xdYFA==
From: <>
To: <>
Cc: <>,

How do I determine why some, not all,  emails are being retruned as undeliverable to the people who are trying to send to us?  An expamle of the header from one of those is below:

Reporting-MTA: dns;

Final-Recipient: rfc822;
Diagnostic-Code: smtp; 454 5.7.3 Client was not authenticated.
Remote-MTA: dns;
Action: failed
Status: 4.0.0

Final-Recipient: rfc822;
Diagnostic-Code: smtp; 454 5.7.3 Client was not authenticated.
Remote-MTA: dns;
Action: failed
Status: 4.0.0

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Check how Exchange is set up for authentication and relaying.  In Exchange System Manager go to (left hand pane) Servers > Your server name > protocols > smtp >  smtp virtual server , then right click the smtp server and choose properties

On a server that is directly connected to the internet you need to do this:

 In the access tab, under authentication make sure anonymous access is checked, or else only computers that authenticate will be able to send mail to your network, not allowing anonymous access will prevent you receiving mail from the outside.

Also check (again under the access tab) that in the relay restrictions you have it set to "only the list below" with your servers IP address/es and any other IP addresses that need to be able to relay through the server.

Finally check that the "allow all computers that successfully authenticate to relay" button is checked for Pop and Imap mail

Hope this helps


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pklein22Author Commented:
Thanks, that was it problem with the setup for the mail2, the second issue.  The first issue, I am now questioning if it is really on my side or on the customers.  As you can see, the email was delivered to our email server the day and time it was delivered to our employee.  The customers email server did not deliver to our email server until approx 24 hours after the customer sent it to us.  
You are welcome and thank you for the points

As far as the second question goes, I would definitely not worry as the  headers show that it was only passed to your server a short while before delivery. That is something that you would have no control over and it can happen for any number of reasons

Good luck with the support!
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