The Microsoft Exchange Server 2010 Protocol technical documentation set provides detailed technical specifications for Microsoft protocols and extensions to industry-standards or other published protocols that are implemented and used in Microsoft Exchange Server 2010.
This allows the user to interoperate or communicate natively with Microsoft Office client and other server products. The documentation is designed to describe each protocol in detail as it is used by the Microsoft Exchange Server. Each protocol specification documents the technical requirements, limitations, dependencies, and Microsoft-specific protocol behavior.
The documentation set includes a set of companion overview and reference documents that supplement the technical specifications with conceptual background, overviews of inter-protocol relationships and interactions, and technical reference information.
You can download it from: Microsoft Download Center