rpcbindsocket

rpcbindsocket is a network service that facilitates the Remote Procedure Call (RPC) mechanism. It acts as a binder, allowing RPC clients to locate and connect to RPC servers. When an RPC server program starts, it registers itself with the rpcbindsocket service, providing information about the services it offers and the network addresses where it can be reached. Clients that wish to invoke a procedure on a remote server first contact rpcbindsocket to obtain the server's address and port. Once this information is obtained, the client can then directly communicate with the server to make its RPC calls.

The rpcbindsocket service typically listens on a well-known port, such as port 111, on all network interfaces of a host. This central registry is crucial for dynamic RPC environments where server processes might start and stop, or change their network locations. Without rpcbindsocket, clients would need to know the specific port of every RPC service they intend to use, which is impractical. The protocol used by rpcbindsocket itself is also an RPC-based protocol. Security considerations are important when running rpcbindsocket, as it can be a target for denial-of-service attacks or unauthorized access if not properly configured and protected.