Microsoft Knowledge Base Article 832017 contains the following summary:
This article discusses the network ports and protocols that are used by server products and their subcomponents in the Microsoft Windows server system.
The Windows server system includes a comprehensive and integrated infrastructure that is designed to meet the requirements of developers and of information technology (IT) professionals. This system is designed to run programs and solutions that information workers can use to obtain, to analyze, and to share information quickly and easily. These Microsoft server products use a variety of network ports and protocols to communicate with client systems and with other server systems over the network. Dedicated firewalls, host-based firewalls, and Internet Protocol security (IPSec) filters are other important components that are required to help secure your network. However, if these technologies are configured to block ports and protocols that are used by a specific server, that server will no longer respond to client requests.