Microsoft wrote: Audience Profile The Microsoft Certified Systems Administrator (MCSA) and Microsoft Certified Systems Engineer (MCSE) on Microsoft Windows Server 2003 credentials are designed for IT professionals who work in the typically complex computing environment of medium to large companies. A candidate for this exam should have at least one year of experience implementing and managing an Exchange messaging system in environments that have the following characteristics: • 250 to 5,000 or more users • Three or more physical locations • Network services and resources such as multiple versions of Exchange Server, Active Directory, proxy server, firewall, other messaging systems, DNS, Internet, intranet, and mobile client computers • Three or more domain controllers • Two or more Exchange Server computers • Connectivity requirements such as connecting branch offices and individual users in remote locations to the corporate network and connecting corporate networks to the Internet