What Is RPC

What Is RPC?

RPC is an interprocess communication (IPC) method that is used by clients and servers to communicate with each other. Simply put, RPC is used by programs, typically on a client computer, to execute a program on a server computer. For example, Microsoft® Outlook® clients communicate with Microsoft Exchange Server using RPC. The client computer sends a message to the server computer with certain arguments. The server responds to the client with a message that contains the results of the executed program.

Integral to this process is the endpoint—the name, port, or group of ports on a computer that is monitored by a server for incoming client requests. More specifically, it is a network-specific address of a server process that is used for RPCs.

The Endpoint Mapper, which is part of the RPC subsystem, is responsible for responding to the clients’ requests to resolve dynamic endpoints. In some situations, Endpoint Mapper is also responsible for dynamically assigning endpoints to servers.

Another important RPC component is the Locator Service. It maintains a list of RPC services and servers on the network. A Windows® client connects to the domain controller over the Server Message Block (SMB) ports (TCP 139 and 445) and searches for RPC services or servers through the Locator Service.

Most built-in Windows services communicate with each other using RPC. For example, certificate services, DCOM, FRS, MSMQ, MAPI, and Active Directory® Replication Service use RPC for communication. Therefore, if the RPC service is not functioning properly on a network, you may experience any number of communication problems.

from : http://technet.microsoft.com/en-us/magazine/2007.07.howitworks.aspx