In environments like virtual classrooms and defence areas, an ad-hoc cloud is increasingly being deployed. Ad-hoc cloud is prone to Denial of Service (DoS) attacks caused by addition of illegitimate clients to the cloud and busty requests from a single or multi-client. In this paper a client transparent approach is proposed using enhanced port hiding technique to mitigate these attacks and attain high performance in the ad-hoc cloud. Admission control is performed to bring control on the number of clients joining the ad-hoc cloud. A fair service to all requests of clients is achieved by a combined scheduling and congestion control mechanism for which wireless Greedy Primal Dual Algorithm (wGPD) is deployed and the algorithm achieves a greater hit ratio of 85 percent. A modified RTS/CTS technique suiting ad-hoc environment is also discussed to handle the hidden and exposed terminal problems.