Abstract: The evolution of grid technology has promoted the changes in the architecture and application environment of cluster systems. These changes introduce new system-level issues to be addressed, including secure, controllable and efficient service access. Traditional access control systems can not satisfy the requirements of applying high performance computers in grid environment due to their weak authentication and coarse granularity of access control. The grid router component of Dawning 4000A discussed in this paper provides a solution to these problems in an application independent manner, by providing strong PKI and grid key based authentication and fine-grained service access protection.