Daily Archives: March 9, 2005

Exchange 2003 mixed mode and native mode

Daniel mailed me about his Exchange 5.5 migration which isn’t going too well and he was getting in a bit of a mess with mixed mode and native mode. Here are a few of the differences…. 

Exchange 2003 Considerations for Mixed and Native Mode

After you migrate from Exchange 5.5 to Exchange 2003, by default, your organization runs in mixed mode. Running Exchange 2003 in mixed mode has the following disadvantages:


  • Exchange 5.5 sites are mapped directly to administrative groups.
  • Administrative groups are mapped directly to Exchange 5.5 sites.
  • Routing group membership consists only of servers that are installed in the administrative groups.
  • You cannot move Exchange 2003 servers between routing groups.


Because many Exchange 2003 features are available only when you run your Exchange 2003 organization in native mode, it is recommended that you switch from mixed mode to native mode. Running Exchange 2003 in native mode has the following advantages:

  • You can create query-based distribution groups. A query-based distribution group provides the same functionality as a standard distribution group. However, instead of specifying static user memberships, with a query-based distribution group you can use an LDAP query to build membership in the distribution group dynamically. For more information about query-based distribution groups, see “Managing Recipients and Recipient Policies” in the Exchange Server 2003 Administration Guide (http://web.archive.org/web/20051210052427/http://go.microsoft.com/fwlink/?linkid=21769).
  • Your routing bridgehead server pairs use 8BITMIME data transfers instead of converting down to 7-bit. This equates to a considerable bandwidth saving over routing group connectors.
  • The Exchange store in Exchange 2003 ignores and removes zombie access control entries (ACEs) from the previous Exchange 5.5 servers in your organization automatically. These zombie access control entries are security identifiers from previous Exchange 5.5 servers that have been removed from your organization.
  • Routing groups can consist of servers from multiple administrative groups.
  • You can move Exchange 2003 servers between routing groups.
  • You can move mailboxes between administrative groups.
  • Simple Mail Transfer Protocol (SMTP) is the default routing protocol.

  Here are some links to articles about these modes:

Mixed mode vs. native mode in Exchange Server 2003

Overview of the Differences between Mixed Mode and Native Mode in Exchange Server 2003

XADM: Mixed Mode vs. Native Mode

Exchange 2003 Deployment Guide – Chapter 4: Migrating from Exchange 5.5