How to Configure Multiple Domains in Exchange 2003 for Hosting

Microsoft Exchange
Hello All: I am new to Exchange 2003, so please help me. We are running exchange 2003 on windows 2003 server. We have one domain and would like to add a second domain to host a newly acquired company. However, Management would like to keep to two companies separate. Meaning the exisitng clients will keep their email addresses and the second domain will contain the newly acquired users. I come from an Exchange 5.5 environment and need detailed instructions on how to accomplish this. Your assistance is greatly appreciated.

Answer Wiki

Thanks. We'll let you know when a new response is added.

I am not exactly sure what you mean by keeping the companies separate however adding a new email domain is fairly easy.

Go to Exchange System Mananger / Recepients / Recepient Policies.

There will be at least a “Default Policy” You will probably want to create a new policy so that you can assign specific users to the policy. YOu assign users by clicking modify at the General tab. When you have created the policy you then add a new SMTP address matching the new domain.

These are the basics. Someone else may need to help you with more detailed information.

Discuss This Question: 2  Replies

There was an error processing your information. Please try again later.
Thanks. We'll let you know when a new response is added.
Send me notifications when members answer or reply to this question.
  • PDMeat
    I've not actually done this myself but exchange supports multiple domains in a single forest and you can only have one exchange org per forest. If all you wanted to do is to control a person's account so that the default send "from" address is "" instead of "", you should just create a second (or third, etc) recipient update service so that when new users are created in that domain they get the other default sender address domain. Another option is to just go into each acquired_co user account and uncheck the box for the RUS to automatically update their addresses and just manually change the default SMTP address yourself. You can still use one SMTP server ( for sending and receiving mail as long as you point the internet MX for to an A record that is a SMTP server for It's up to you and your boss if you want to host the users on another server possibly in another exchange administrative group. Email disclaimers and/or content scanning will require a little thought too, if you use those services.
    0 pointsBadges:
  • AdTechJO
    It is not clear what your administration wants. If they actually want two different domains that recquires that members do not have access to the other domain resources then you need to set up new domain controller separate of the other. Of course you can then install a separate exchange server. You can use System Manager to control and manage both by giving spcific trust to administrator in both domains. If you need to separate the emails only, set a domain as company.loc whereby all users are listed. Then in the exchange setup two different connectors each responsible to receive that specific domain ( and ( You need to setup two policies each with the different email domain. When applied, you reset each user email as primary email domain to that specific respective one Clear out what the administration wants really!! good luck
    0 pointsBadges:

Forgot Password

No problem! Submit your e-mail address below. We'll send you an e-mail containing your password.

Your password has been sent to:

To follow this tag...

There was an error processing your information. Please try again later.

Thanks! We'll email you when relevant content is added and updated.


Share this item with your network: