When your network grows and it begins to expand from a single server-based system, you will want to make sure that you retain your electronic mail service. This chapter sets down some basic guidelines that will show you how to plan for the expansion of your post office system, how to deal with multiple post offices and how to connect different mail systems together.

It is aimed at those network managers that need to expand their mail service over the functionality provided by the basic Exchange client. In upgrading to a server-based post office, you have to consider gateways, fault-tolerance, network traffic and mail standards.