Hello, We have Exchange 2010 with SP2. For the last couple of weeks we are sending emails to an external client (e.g. xyz@external.com). Just 2 days back we came to know that the actual email id of the client is not xyz@external.com but it is abc@external.com. When we had sent the earlier emails we did not get any bounce back email from that domain. I want to know how is this possible. If this can be true then where will all the emails sent to xyz@external.com get stored in Exchange. Kindly suggest.

Have you checked the queues in Exchange? Also, some organizations can 'blackhole' emails when they go to users not in the directory by not sending back an NDR message.JAUCG

On Tue, 29 May 2012 10:45:33 +0000, AmitAggarwal wrote: >We have Exchange 2010 with SP2. For the last couple of weeks we are sending emails to an external client (e.g. xyz@external.com). Just 2 days back we came to know that the actual email id of the client is not xyz@external.com but it is abc@external.com. When we had sent the earlier emails we did not get any bounce back email from that domain. Not every domain sends a NDR, and not every domain sends a 4xx or 5xx status code in response to an unknown address. >I want to know how is this possible. If this can be true then where will all the emails sent to xyz@external.com get stored in Exchange. In the sender's mailbox. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

On Tue, 29 May 2012 10:45:33 +0000, AmitAggarwal wrote: >We have Exchange 2010 with SP2. For the last couple of weeks we are sending emails to an external client (e.g. xyz@external.com). Just 2 days back we came to know that the actual email id of the client is not xyz@external.com but it is abc@external.com. When we had sent the earlier emails we did not get any bounce back email from that domain. Not every domain sends a NDR, and not every domain sends a 4xx or 5xx status code in response to an unknown address. >I want to know how is this possible. If this can be true then where will all the emails sent to xyz@external.com get stored in Exchange. In the sender's mailbox. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

hi, >>>Just 2 days back we came to know that the actual email id of the client is not xyz@external.com but it is abc@external.com. Can you make sure that the address xyz@external.com is not exist? If it is really not exist. Yes, like others say not every domain will send back NDR. You also can change the settings via your EMC. I think these message are still in the unreachable queue. You can use the tool in the EMC to check. hope can help you thanks,CastinLu TechNet Community Support

Let me explain our setup: We have Exchange 2010 with SP2 and use Ironport as gateway. Recently I sent an email to xyz@externaldomain.com, and the email has gone from the Exchange and Ironport both. We got deliver notification at Ironport that the email has been delivered to externaldomain. But later the client said that his email id is different abc@externaldomain.com. Our server is capable of generating NDRs. It's been more than 3 months but we haven't received any NDR till date for email sent to xyz@externaldomain.com. When we do a telnet and type this email id in rcpt to, we get recipient ok response. Now the sender and receipient wants to know where they can find the email and why the NDR was not generated. I have checked all the queues, but nothing is there.

If you telnet to their server and get an OK when you send to that non-valid recipient, then the problem is not yours, it is with the configuration of their server. The recipient needs to take it up with their email server admins. Exchange has done its job, it has delivered the email. The problem is exclusively with the recipient. Most likely the messages have been silently dropped, as there are a large number of mail administrators who think that it is a good thing to just drop email for non-valid recipients. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

If you telnet to their server and get an OK when you send to that non-valid recipient, then the problem is not yours, it is with the configuration of their server. The recipient needs to take it up with their email server admins. Exchange has done its job, it has delivered the email. The problem is exclusively with the recipient. Most likely the messages have been silently dropped, as there are a large number of mail administrators who think that it is a good thing to just drop email for non-valid recipients. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

hi, Sorry, my fault. If you can receive NDR, the message will stay at your unreachable queue. If you can't receive NDR, it seems the message has been delivered to the remote server and the server has accepted it. The reason for that why you can't receive NDR is probably the remote server has configured not send NDR. hope can help you thanks,CastinLu TechNet Community Support

As was suggested multiple times, it appears to be a configuration setting on the destiantion server. What kind of mail server do they have?JAUCG

As was suggested multiple times, it appears to be a configuration setting on the destiantion server. What kind of mail server do they have?JAUCG