Applications
In the Microsoft universe, many companies provide hardware and software support. The number of applications that are available to run in the Server 2003 environment are numerous. There are financial apps, database programs, and e-mail exchange operations as well as web server and Internet programs.
Security
Domain operations are an important resource available on the network through Server 2003. Making Server 2003 a domain controller adds security and the ability to add local and group policies to the network. If Server 2003 is not promoted to the status of a domain controller, then it can run simple network operations using peer-to-peer structures. These are workgroups, and they can only block or allow access but do not provide control features for the network.
Windows Server 2003 local policies have the ability to perform certain operational commands. For example, some of the operations available are rebooting a remote server, using remote desktop operations, or adding and removing other users and computers. These are operations available to the domain controller network system. This means that Server 2003 can centralize user and computer access. Only one machine needs to be configured as the Domain Controller rather than all machines on the network.
Reliability and Downtime
As for reliability, Server 2003 is very reliable. The uptime on Windows 2003 Servers is about 99.993%. On a yearly basis, that means that the server is roughly down about 40 minutes per year. And this downtime is only that much because the reboots may take 6 minutes or so to fully restart the system.