A system and method for transferring data and messages between nodes in a cluster is disclosed. Each node in the cluster is a separate physical domain but is connected to other nodes in the cluster through point-to-point high speed links. Each side of a link is coupled to a coprocessor which facilitates the movement of data between and among the nodes. Because each physical domain is separate from any other domain, the coprocessor in a physical domain uses a certificate, called and RKey, to obtain permission to transfer data to another physical domain. When an RKey is received from another physical domain, the coprocessor in the receiving domain validates the key and obtains the physical addresses associated with the key so that it can provide or accept the remote data. Data transfers between pairs of remote nodes in the cluster are permitted as well.