Techniques for detecting and mitigating Denial of Service (DoS) attacks in distributed networking environment are disclosed. In certain embodiments, a DoS detection and mitigation system is disclosed that automatically monitors and analyzes network traffic data in a distributed networking environment using a set of pre-defined threshold criteria. The system includes capabilities for automatically invoking various mitigation techniques that take actions on malicious traffic based on the analysis and the pre-defined threshold criteria. The system includes capabilities for automatically detecting and mitigating “outbound” DoS attacks by analyzing network traffic data originating from an entity within the network to a public network (e.g., the Internet) outside the network as well as detect and mitigate “east-west” DoS attacks by analyzing network traffic data originating from a first entity located in a first data center of the network to a second entity located in a second data center of the network.