What is Stateful Inspection?

Stateful inspection, also known as dynamic packet filtering, is a technology (i.e. in NGFW) that monitors the state of known active connections and uses this information to determine which network packets to allow through. State-heavy devices such as network firewalls do not work well for DDoS defense, as the state they carry can easily be exhausted by attackers, leading to a complete outage of protected assets; rather, intelligent DDoS mitigation systems (IDMSes) such as NETSCOUT TMS and AED/APS are optimized for DDoS defense, and can defend stateful devices against DDoS attacks, when necessary.