Securing wireless mesh networks is a more challenging and complex issue due to their inherent characteristics such as shared wireless medium, multi-hop, and inter-network communication, highly dynamic network topology and decentralized architecture. These vulnerable features lead to several types of attacks like backhole, grayhole, wormhole and rushing attacks in the network layer. Out of all these attacks, rushing attacks are more difficult to detect due to the difficulty levels to find the exact processing delay at each node in WMNs. Existing security mechanisms to protect against the rushing attacks suffer from high false positives, false negatives and control overhead. In this paper, we proposed a trust-based IDS for rushing attack. The key functionalities of the trust-based IDS are 1) placing the optimal number of trust nodes and 2) Based on the node behavior, dynamic reputation is implemented on node independent and node dependent IDS approaches to identify and isolate the rushing attacks. Our Simulation results show that our proposed IDS secure the network performance such as throughput and packet delivery ratio even in the hostile environment.