The components of communication network device ingress systems and methods cooperate to manage information ingress and prevent denial of service attempts. A classifier classifies incoming information. A classification filter filters the information on a classification basis to prevent denial of service. The classification filter includes a classification filter counter for tracking the flow of information associated with the classification filter. A zero value in the classification filter counter indicates that a buffer capacity limit associated with the classification is reached. The counter permits information to flow to a packet buffer if the classification filter counter value is not zero and discards information if the classification filter counter value is zero. In one exemplary implementation the classification filter counter decrements a classification filter counter value when the information is placed in the buffer. The classification filter counter value is incremented when the information is processed out of the buffer.