I have already installed Exchange 2010 in a practice environment "New Domain, New Forest" and got the server working perfectly. We are planning on installing Exchange 2010 on existing domain. Our existing domain is "company.domain" I'm planning on intgration with our existing domain users. Our mail domain name is companymail.com. Question: Is it good practice to create a new domain in our existing forest called 'companymail.com' so I can get intergration with our existing domain user or do I join our existing domain?

Which domain you will be using in production for emails? What are you trying to achieve? At the end of the day you want exchange 2010 as your production server, right?Gulab Prasad, MCITP: Exchange Server 2010 | MCITP: Exchange Server 2007 MCITP: Lync Server 2010 | MCITP: Windows Server 2008 My Blog | Z-Hire Employee Provisioning App

Hi >> Is it good practice to create a new domain in our existing forest called 'companymail.com' so I can get intergration with our existing domain user or do I join our existing domain? I would say that the best solution is to install Exchange in the same domain as your users unless you are trying to achieve something specific. Cheers, Steve

Hi Normski, Yes, I agree with steve. the best solution is to install Exchange in the same domain for your users. but if you need users (in companymail.com) can use mailboxes on the Exchange (in company.domain), you also can use linked mailbox to do that. Create a Linked Mailbox http://technet.microsoft.com/en-us/library/bb123524.aspx Thanks, Evan Liu TechNet Subscriber Supportin forum If you have any feedback on our support, please contact tngfb@microsoft.com Evan Liu TechNet Community Support

Hi Normski, Any updates on this issue? Thanks, Evan Liu TechNet Subscriber Supportin forum If you have any feedback on our support, please contacttngfb@microsoft.com Evan Liu TechNet Community Support

Ok, I'm still a bit wholly on the issue, which option do I use o Existing Forest o Add a domain controller tp an existing domain o Create a new domain in a existing forest This server will become the domain controller in the new domain o Create a new domain in a new forest. In the test environment I used the latter option. If I integrate Exchange into my existing domain what happens if the DC becomes unavailable are users still able to access their mail?

If I integrate Exchange into my existing domain what happens if the DC becomes unavailable are users still able to access their mail? Which DC become unavailable, the DC in the new foreast? If the DC (in new forest) become unavailable, user will not be able to access their mail. because when you use linked mailboxes, Exchange Server still need to check users in AD, if DC is unavailable, it cannot find the linked master account. Thanks, Evan Liu TechNet Subscriber Supportin forum If you have any feedback on our support, please contacttngfb@microsoft.comEvan Liu TechNet Community Support

So my best guess to improve resilience is to deploy as "Create a new domain in a new forest" and not have linked mail boxes. Basically I'll be using Exchange in isolation which I actaully acheived in a test enviroment. Would this seem a fair solution to use.

Yes, the best solution is to install Exchange in the same domain as your users. Thanks, Evan Liu TechNet Subscriber Supportin forum If you have any feedback on our support, please contacttngfb@microsoft.com Evan Liu TechNet Community Support

Hi, the best option is installed exchange in your existing domain/ forest & add all the user mailbox simple using exchange management console, for continuaty of user login when DC become faliure, you can create an ADC in your existing domain/forest. I think this is the best solution, try this & if you have any problem let me update. Thanks & if you find this helpful mark it as an answer Cheers....Arun Chaudhary MCP,MCTS Win Server 2008,MCITP Exchange 2010 Visit my Blog- http://arunmsexchange.blogspot.in

I agree with Evan. You should have a single domain which includes your users and Exchange servers. To improve resilience you should add extra domain controllers not extra domains. Cheers, Steve

Hi Normski, How about the issue, any updates? Thanks, TechNet Subscriber Supportin forum If you have any feedback on our support, please contacttngfb@microsoft.comEvan Liu TechNet Community Support