At the Fork In the Exchange Migration Path

The road behind has no signposts for what's to come.

• By Bill Boswell
• June 24, 2003

I'm moving our network from mixed to native because our Exchange server is 15.3 G. I've read that Exchange can run in a mixed environment—yes or no? In one article I've read, it says that if you are a member of the Enterprise Domain, Administrators, Domain Admins and Exchange Admins that you will not have to run forestprep and domainprep runs when you first try to install Exchange 2000. Will this let me install Exchange 2000 in a mixed environment and move mailboxes from my Exchange 5.5 SP4 server, or will I have to be in native mode?
—Russ Moss

I want to ask you for a recommended upgrade path for Exchange 5.5 to Exchange 2000. My company is preparing to migrate to Exchange 2000 and have had varying opinions. Some say the best approach is to install Exchange 2000 on a separate box and install the AD connector. Others have recommended doing a full migration by creating the Exchange 2000 box, ex-merging all mailboxes out and importing them into Exchange 2000. Do you have a recommended approach or is it simply a matter of preference?
— Marty Kineen, MCSE, CCNP
Plymouth Meeting, Pennsylvani

Russ and Marty,

Your questions are somewhat related. You both are running legacy Exchange in a Windows 2000 domain and you're looking for the most efficient upgrade path.

Russ, you'll need to shift your domain to Windows 2000 native mode so that you can create Universal security groups to act as Exchange 2000 distribution lists. This means you must either upgrade or decommission your NT BDCs, then shift the domain to native mode. This shift does not impact down-level clients nor does it affect the Exchange 5.5 server.

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Marty, in the configuration you've described, the upgrade path that gets you to a full Exchange 2000 deployment with the least hassle would be to introduce a new Exchange 2000 server into the existing sites and use the Active Directory Connector (ADC) to keep the legacy Exchange directory service in sync with Active Directory during the migration. You shouldn't need to create a separate Active Directory domain or a separate Exchange organization. Once the Exchange 2000 server is in place, move all the mailboxes and connectors from the legacy Exchange server then decommission the server and shift to Exchange Native mode. The documentation walks you through this process.

As for running Forestprep and Domainprep, it's true that both of these actions are performed when you run Exchange 2000 Setup so you do not need to run them separately. The documentations calls them out individually because many organizations divvy up their admin rights so that one account doesn't have the necessary permissions to do both. In a single domain configuration, the simplest way to do the ADC installation and the Exchange 2000 setup is to use the Administrator account for the domain. This account has full access to the Schema, to the Configuration container where the Exchange organization will be created, and to the Domain container where the Exchange system accounts will be created. The ADC requires a service account in Active Directory that has Service Account Admin permissions in the legacy Exchange organization, sites, and configuration container.

Before you can run Exchange Setup, you’ll need to install the ADC and create recipient and public folder connection agreements to each of your sites. You should be running Exchange 5.5 SP3 or higher on at least one Exchange server in each site, although I recommend getting all your Exchange servers to the latest service pack prior to deploying Exchange 2000.

The ADC modifies the schema, so you'll need to run it using an account that is in the Schema Admins group. Plus you'll need admin rights for the Configuration container. The simplest way to do this is to use the Administrator account for the domain. When you run Exchange Setup, you’ll modify the schema again so the same permission rules apply.

Good luck and let me know how things turn out.