A method for communication, includes allocating, in a network interface controller (NIC) a single dynamically-connected (DC) initiator context for serving requests from an initiator process running on the initiator host to transmit data to multiple target processes running on one or more target nodes. The NIC transmits a first connect packet directed to a first target process and referencing the DC initiator context so as to open a first dynamic connection with the first target process. The NIC receives over the packet network, in response to the first connect packet, a first acknowledgment packet containing a first session identifier (ID). Following receipt of the first acknowledgment packet, the NIC transmits one or more first data packets containing the first session ID over the first dynamic connection from the NIC to the first target process. Dynamic connections with other target processes may subsequently be handled in similar fashion.