Hi, Our Exchange 2010 infrastructure have 2xedge, 2xms, 2xhub, 2xcas and 2xad. Sending mail to external domains to internal domain was no issues. However, we encounter an issues with local delivery of domain not pointing to our MX records. For example: we have hosted two domain1.com and domain2.com at server. The domain2.com was just added (assuming all the mailbox users added ) and the MX records haven't point to our exchange and it still hosted at outside (others hosting provider) . The problem was when the domain1.com sent email to domain2.com it will delivery to the domain2.com at our exchange and routed to their hosting provider. Is it possible can create any rules to force those local mail domain to check the MX records before deliver to the mailbox? Does any send connector rules or transport rules can solve this issues? Please comments if you have any idea, Thank You!

Hi, This article explains whats need to be done http://technet.microsoft.com/en-us/library/bb676395.aspx Leif

Hi Leif, Thanks for the feedback! We have gone through the articles given which means that in order to solve the issues, we have to enable the Internal relay domain for which site are hosted their mx records outside our exchange organization. By enable this options customers at this domain will receive duplicate email (1 from our mail server another 1 from their email hosting provider), am I right to said that? Assuming both hosting provider have all the mailboxes. Is it the only way to solve our issues?

Hi, I don't believe so. You change the domain to be an internal relay domain. This means that when an internal user sends an e-mail to one of the addresses this will happen: Exchange will check to see if the mailbox is located internally - if yes the mail is delivered directly to the mailbox - if the mailbox is not hosted locally the mail will be sent to the external account. If an external user sends an e-mail to the address. Mail will be sent to the hosting provider - it is then his job to forward the e-mail to the exchange environment if the mailbox is not located at the hosting provider This solution is the only way to solve your issue Leif

Hi, How about if we disable the mailboxes at our Exchange environment? when other domains at our exchange environment send mail to this domain which enable internal relay domain will the sender get bounce back email? Or the email will route to external account?

Hi, If you disable the mailboxes in your environment (meaning removing the specific e-mail address from the user) the mails will be sent to the external account. This happens because of the internal relay configuration and because the address doesn't exist in your environment. Leif

Hi, What I means is disable the mailboxes without remove them from our exchange environment. As this the way to force the mail sent to external account. Does this method work?

Hi, If you by disable the mailbox mean disable the user account - this won't work as the users are still known in the environment. You can remove the external address on the mailbox and then add this as the forwarding address. That should work. Another thing. Instead of having the externall hoster configure forwarding it might be easier if you configure the MX record to point to the exchange environment. In this case you will get all external e-mails for the domain delivered and you decide which mails need to be sent external again. Leif

Hi, Thank you Leif! In that case, we will consider remove the external accounts.