HiWe are running Exchange 2003. Users are split over multiple Exchange servers.I have a DL - "All Staff", this is a restricted DL and only I can send to it. "All staff" is made up of two smaller DL's, "All Staff (A-M)" and "All Staff (N - Z)". These are also restricted, and no one can send to it (not even me, for testing purposes).I notice that if I send an email to "All Staff", the messsage is not delivered to recipients, but I do not receive an NDR. If someone else tries to send to "All Staff", then recieve an NDR. If I add myself to restriction list on the two sub DL's, then the message is delivered.Does anyone know why no NDR is received in the first instance?Secondly, when Exchange needs to expand the list of recipients, where does it do this?And finally, how is the message sent, is it sent to everyone at the same time, or does Exchange work through the list of the DL's? So, for instance, the second sub DL hasUser1User2User3....User1000Does it send the message to User1 - User1000 at the same time, does it send to User1, then User2 etc (albeit the difference being microseconds) etc?Finally,since there are so many people in these DL's who are going to be on holiday, mailbox full etc, is there any way to prevent the DL's from generating NDR's if any of the recipients are unreachable?Hope someone can help!thanks.

Hi, Regarding the first question, I would like to explain that I am not able to reproduce your issue on my lab. Based on my test, I am able to receive NDR message indicated that I have no permission to send email to sub distribution list. Therefore, would you please let me know the Configuration of the All Staff, "All Staff (A-M)" and "All Staff (N - Z)" Distribution Groups? Please check whether the Do not send delivery report option is selected under Exchange Advanced tab of All Staff group property. Regarding the second question, please understand when a message is sent to a distribution group, the Exchange message categorizer checks if the distribution group must be expanded locally or remotely. If the expansion server is set to Any (without the quotation marks), the sending server expands the distribution group. If the expansion server is set to a specific server, one copy of the message is sent by using SMTP to the specific expansion server for expansion. The message categorizer of the expansion servers retrieves the list of members from the member attribute of the distribution group. To read from the global catalog, the message categorizer uses the security context of the LocalSystem account that the Simple Mail Transfer Protocol (SMTP) service runs under, and that represents the permission that the Domain\Exchange$ account has. The message categorizer retrieves the list of members and converts the distinguished names (DNs) to Relative Distinguished Names (RDNs), and then runs a batched LDAP search on the global catalog server to retrieve attributes that are required to route mail to recipients. For your reference: Troubleshooting mail transport and distribution groups in Exchange 2000 Server and in Exchange Server 2003 http://support.microsoft.com/kb/839949/en-us Regarding the third question, I would like to describe the process when a message is sent to a distribution group. I assume that we have following environment: Two Exchange Servers in same Routing Group (Exch01, Exch02) A Distribution Group (DL1) with 4 Users (A and B on Exch01, C and D on Exch02) When user A deliver a message to the Distribution Group (DL1), the message is submitted to Exchange Server (Exch01). At categorization stage, the Exchange server expands the Distribution Group (DL1) to four recipients. Then, it query AD and know that the UserA and UserBs mailboxes are on the local server and the UserC and UserDs mailboxes are on the Exch02 server. Then, the Exchange server bifurcate the message to two copies. One copy is delivered to local store and another one is delivered to Exch02 through SMTP. Note: Please understand that when the message is delivered to local store with two recipients, actually only one message is saved to the store. Please understand that the Exchange store was structured into various tables such as Folders Table (Inbox, Outbox and so on), Message Folder Tables (For example, the message entries in the inbox folder of UserA), Message Table and Attachment Table. The message body is saved in the Message Table and the entries in Message Folder Table point to the message in the Message table. Regarding the last question, I would like to explain that you can configure Distribution Group Do not send delivery report under the Exchange Advanced tab. Mike