Systems and methods for improving the performance of DDoS mitigation by monitoring the health of a protected network resource are provided. According to one embodiment, health of a network device protected by DoS mitigation device can be evaluated and packet/traffic received on the DoS mitigation device can be selectively/conditionally forwarded to the protected network device or can be dropped based on the health of the protected network device. According to one embodiment, at-least a part of the traffic is blocked when the health of the protected network device is below a predetermined health threshold. In an exemplary implementation, a measure of volume of traffic originated by different computing devices and handled by the protected network device can be computed, and packet filtering or conditional forwarding can be enabled when the computed measure of volume of traffic exceeds a predetermined traffic volume threshold.