Du et al. put forward a solution to solve the slow access to the campus network. This solution offered a novel approach to complete NA T Traversal of the second export of the campus network and a good idea based on virtual private network (VPN) to realize the outer network can rapidly access the campus network with any application layer protocols, e.g., HTTP, FTP. A VPN solution based on UDP tunnel and Open VPN tap interface is designed and implemented to achieve above mentioned goal in this paper. We package the OpenVPN Tap interface into a Dynamic Link Library (DLL) and program an VPN client and server in Java by calling our DLL API. Performance of the UDP-based VPN solution is evaluated and compared in a real network environment and between the campus network and the outer network. The results show that our solution is effective and can satiW' the actual requirements of network applications.