Hi all,

I'm currently in the beginning phase of running coexisting Exchange 2003 and Exchange 2010. I have an interesting problem which I was hoping you'd be able to offer some insight into:

If I create a mailbox on 2010, it is fully able to send mail out to the internet, and receive and send mail from 2003. However, if I try to send a mail from the internet (so an external address) to the newly created mailbox, it simply never arrives. If I try again 24 hours later, it works without a problem! What happens overnight to be able to allow this?

We have a proof point firewall sitting in the perimeter which says all mail goes to the Exchange 2003 server, so I thought that may be preventing mail from reaching 2010 mailboxes...however that does not explain why it works after 24 hours!!

Any ideas?

Many thanks,

Nathan

Hi,

Id like to confirm your current mailflow, if it is not correct, please let me know.

Internet ->Exchange 2003 ->Exchange 2010

Please enable the protocol logging and see where the message stuck:

http://support.microsoft.com/kb/821910/en-us

Thanks,

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