The Multi-hop wireless networks or ad hoc networks are build on MAC IEEE 802.11 DCF protocol, which was originally designed for wireless LAN. This adaptation have revealed problems and vulnerabilities that a based on traffic DoS attack might take advantage, avoiding normal clients to access or provide its services. In wired networks, hardware devices and preventive measures like encryption and authentication are used to the defense against the attacks, but sometimes due of ad hoc networks physical conditions, this measures could not be applied, then the network performance falls. For the simulations of basedon traffic DoS consequences on MAC layer protocol, Qualnet® simulation tool was used. To improve the performance of the multi-hop network in presence of a based on traffic DoS, we propose as a preventive measure to increase and setup the default retry limits of MAC layer and a modification of BEB algorithm. These changes, reduce the effects of the DoS and improve the network performance in terms of throughput and packet delivery ratio.