A method, programmed medium and system are provided for preventing the denial of file system access to a plurality of clients accessing a NFS server. In one example, an NFS server is configured to listen on a server port. The server runs a separate daemon which “watches” client requests as they are received at the NFS server. The server processing system tracks the number of times a client sends consecutive TCP zero-window packets in response to a data packet from the server. If the number of zero-window packets crosses a user-defined threshold, then a routine is called to stop responding to that client using a backoff algorithm. When the server reaches a point where the number of available threads or any other relevant resource dips below a user-defined threshold, the server process starts terminating connections to the clients starting from the ones with the oldest entry in the table.