Reconfigurable compute devices, namely Field Programmable Gate Arrays (FPGA), have increasingly been deployed in datacenters and cloud infrastructures. Such devices have proven effective at performing certain types of compute tasks, often performing these tasks faster, with lower latency, at a higher throughput, and/or at lower power than traditional compute devices (e.g. CPUs). Some recent works have demonstrated the benefits of deploying such devices as direct-connected nodes, i.e., the FPGAs are connected directly to the datacenters' network infrastructure. In this work, we introduce the concept of the Network Management Unit (NMU), which secures the network from potentially unwarranted access from malicious or malfunctioning FPGA applications; specifically, the NMU targets network traffic originating from (or targeted towards) an application resident solely on the FPGA itself. We argue that this is a necessary feature of direct-connected reconfigurable compute devices. We present the design of several NMUs, introduce a taxonomy for describing these different designs, and analyze the trade-offs of each design. The NMUs discussed range from those that employ hairpin routing techniques to push management to the next level switch, to those that perform routing and access control directly.