Hi, I have 2 forest for two different companies. There is a forest trust between the two. There is one active exchange 2003 server in one of the domains. Is it possible to use this exchnage server to manage the mailboxes for the users in the other forest domain? Or, do I have to setup an additional exchange server? Thnx. Erik

You can have only one Exchange Org per forest so that other forest will need its own separate Exchange org.

You can have users from the second forest on the Exchange server in the first forest. That would require accounts in the same domain as the Exchange server and the relevant permissions configured. Management of the mailboxes would require the trusted accounts having the relevant permissions in the Exchange org and domain. It will get messy very quickly. If you can configure a dedicated Exchange server, that will be the easiest option. Simon.Simon Butler, Exchange MVP. http://blog.sembee.co.uk , http://exbpa.com/

Hi Erik, Based on your description, I recommend you deploy the resource forest (also known as the dedicated Exchange forest) topology. For detailed, you can refer the following articles, Using a Dedicated Exchange Forest: http://technet.microsoft.com/en-us/library/aa997312(EXCHG.65).aspx Planning to Deploy Exchange in a Multiple Forest Environment http://technet.microsoft.com/en-us/library/bb124677(EXCHG.65).aspx Deploying an Exchange Resource Forest: (The principle is very similar, though it is a instance in Exchange 2007) http://www.msexchange.org/articles_tutorials/exchange-server-2007/planning-architecture/deploying-exchange-resource-forest-part1.html If you have any other question, please do not hesitate to let me know. I am glad to have a further discussion with you. Best regards, Yang