When a client wants to connect to a remote procedure call (RPC) service, it contacts the RPCBIND daemon and requests the address of the service. In this way, addresses can be dynamic and the client does not need to know which port the service is waiting on.
Services need to be registered with the rpcbind daemon in order to be useful. If the rpcbind daemon is inactive, the services are unable to start, and the clients are not able to find any of the services.