Hi GuysI had a query about NDR's I was hoping someone could help me with. Unfortunately, I can't test this out in real life nor can I find the answer on the internet.Let's say there is the set up below:Sender > Internet > SMTP Gateway (smtp.domain.com) > Exchange 2003Bridgehead (gateway.domain.com) > Exch Mailbox 2003server (mail1.domain.com) > OutlookIf the Sender sends an email to the recpient (user@domain.com) and the SMTP gateway is down, then I from what I understand the Sender's MTA will keep trying as defined within the Retry interval/ Expiration timeout.However, what about the following scenarios:1) The mail1.domain.com mailbox server is down. I assume messages get queued at gateway.domain.com, and now gateway's retry settings are relevant? If the message can't be delivered t mail1, will it be gateway that generates the NDR?2) The user's store on mail1 is down. So now the mail *can* reach the mailbox server, but not the actual mailbox. Will an NDR be generated, since technically the message has reached the end server? How long will Exchange keep a message (presumably in the Messages awaiting Local Delivery queue) before it deletes them? What defines this period? Or will it keep them indefinately?3) Does any of this behaviour change with Exchange 2007?

1) If the gateway can not deliver in the defined time, then yes, it will bounce the message back - NDR.2)In this scenario, Exchange will not NDR it. It will just sit in that queue till the store is back up.3) No :)

1) The mail1.domain.com mailbox server is down. I assume messages get queued at gateway.domain.com, and now gateway's retry settings are relevant? If the message can't be delivered t mail1, will it be gateway that generates the NDR? Ans:> Yes by default the 10min is the retry period set on Default SMTP VS 2) The user's store on mail1 is down. So now the mail *can* reach the mailbox server, but not the actual mailbox. Will an NDR be generated, since technically the message has reached the end server? How long will Exchange keep a message (presumably in the Messages awaiting Local Delivery queue) before it deletes them? What defines this period? Or will it keep them indefinately? Ans> Mail has already entered Org it will be Q'd in Local Delivery Q 3>No. But little change in GUI :) Vinod |CCNA|MCSE 2003 +Messaging|MCTS|ITIL V3|

Thanks guys.Just another query regarding question#2:"2) The user's store on mail1 is down. So now the mail *can* reach the mailbox server, but not the actual mailbox. Will an NDR be generated, since technically the message has reached the end server? How long will Exchange keep a message (presumably in the Messages awaiting Local Delivery queue) before it deletes them? What defines this period? Or will it keep them indefinately?"So you guys are saying it will remain in the local delivery queue. How long will it stay here for? I thought messages had some sort of TTL, meaning that they will expire and somehow delete themselves after a certain period? Or is there no such thing and the message just remains in the local delivery queue indefinately?

In my experience, it will just sit in the local delivery queue until the cows come home ( or the store is mounted). However, technically, I believe it's supposed to NDR after 2 days and there have been a number of Exchange hotfixes over the years that address that nagging issue. Personally, I would rather they do not NDR. I figure that once they reach the Exchange Server and are in the local delivery queue, it's my responsibility to make sure they get delivered.

Hi,I have tested on my lab, I found the NDR was generated if the user's store on mail1 is down. The time for that configuration is under SMTP Virtual Server, Delivery tab, Local area.Please note: The default retry time for local delivery queue is 5 minutes which ishard-code, that indicates the time of NDR will be generated is 5 minutes whichmust accord with the defaultretry timeif the configuration is less than 5 minutes. Otherwise, the time of NDR should be the same as the configuration.ThanksAllen

Hi,I have tested on my lab, I found the NDR was generated if the user's store on mail1 is down. The time for that configuration is under SMTP Virtual Server, Delivery tab, Local area.Please note: The default retry time for local delivery queue is 5 minutes which ishard-code, that indicates the time of NDR will be generated is 5 minutes whichmust accord with the defaultretry timeif the configuration is less than 5 minutes. Otherwise, the time of NDR should be the same as the configuration.ThanksAllen 5 minutes for a NDR? What was the total time in the queue before it bounced in your test? Regardless, I have seen those never bounce!

Hi,OK, I would like to give the steps for the testing on my lab:There are two Exchange servers in different domains, a.com and b.com. On the domain b, the Expiration timeout which was configured as 3 minutes,then dismount the mailbox database, simulate the sending email from a.com to b.com. In the ESM of domain b, the message is hung at Local delivery queue with the message stating "8:06 AM" under Time next connection retry, the message reaches to the Local delivery queue is 8:01 AM.From the message tracking, apparently the NDR was generated at 8:06 AM.If the Expiration timeout is configured as 7 minutes, the NDR is generated at 8:27 AM which the message comes into the Local delivery queue is 8:20 AM.Furthermore, I have specified the different time on the Expiration timeout in order to verify the result. The final result is expected as I mentioned above.ThanksAllen

I've got almost the same scenario, but Ihavemultiple mailbox servers, so when an e-mail comes to front-end if responsible mailbox server is down it should then queue it to local delivery and wait until respective mailbox server is up is that correct? Just had an issue when a client received an NDR 4.4.7 when the mailbox was shut down for a day, but noone else reported the problem.Wondering where can I check what timeout is defined for my mail servers' local delivery queue, I feel more comfortable with infinite one.Thanks,Fedor