Planning Your Exchange Infrastructure


Topic Last Modified: 2005-08-19

Before you begin planning your Exchange organization, it is important that you are aware of the topological boundaries and limitations, as well as the known limits for a single Exchange organization. The simpler the design the easier the topology is to maintain. As a general guideline, create as few administrative groups, routing groups, and domains as possible.

Some limits are built into Exchange. A single Exchange organization cannot exceed any of the following limits:

  • 1,000 Exchange servers

  • 1,000 Administrative groups

  • 1,000 Exchange connectors (including third-party connectors) per routing group. Note that connectors should be counted based on their number of directions. For example, a one-way connector counts as one, and a two-way connector counts as two.

  • 100 domains

In addition to the above limits, it is recommended that you:

  • Create no more than 150 routing groups

  • Limit the number of address lists visible to each user to 10 or fewer

  • Limit the number of security groups and distribution groups per user to 80 or fewer

While planning your Exchange deployment, it is important to consider the different design issues that apply to your situation. Large enterprises with complicated network environments, multiple autonomous business units, or other complexities will require more planning and attention to these matters than smaller organizations with relatively straightforward messaging needs. The topics described in the table below will help you understand different aspects of Exchange. Use this information to help plan your Exchange infrastructure. If your environment is complex, spending extra time planning and thinking through these issues will help prevent future problems.


Design Consideration Topic to review

Centralized vs. Distributed Messaging Systems. Which is right for you?

Centralized vs. Distributed Messaging Systems

Routing Design. Efficient routing helps reduce network traffic and your bandwidth constraints effect your routing decisions.

Planning Your Exchange Server Routing Design

Active Directory considerations and Domain Controller placement. You might have chosen to remove your Exchange servers from a branch office, but think twice before moving the domain controller.

Planning Exchange and Directory Server Placement

Capacity Planning. How many servers do you need? There are tools you can use to help determine the number of servers you will need.

Exchange Server Sizing and Tuning

Exchange Server 2003 Performance and Scalability Guide

Front-End/Back-End configurations. If you have multiple servers and provide Internet e-mail access to your users, a Front-End Back-End configuration offers many advantages.

Exchange Server 2003 and Exchange 2000 Server Front-End and Back-End Topology

Availability. If you want an e-mail system to run with minimal interruption you'll need to plan ahead. Decisions about hardware, service level agreements, backup and restore strategies, and so forth are best made before you deploy your first server.

High Availability Guide for Exchange Server 2003

Client Access. Without clients, there is not a lot for your e-mail servers to do. Considering how your particular users will send and receive data will help you make the right decisions as you roll out your Exchange organization.

Client Access Guide for Exchange Server 2003