This is a potential security issue, you are being redirected to https://csrc.nist.gov.
A firewalling capability that improves upon standard stateful inspection by adding basic intrusion detection technology. This technology consists of an inspection engine that analyzes protocols at the application layer to compare vendor-developed profiles of benign protocol activity against observed events to identify deviations, allowing a firewall to allow or deny access based on how an application is running over a network.
NIST SP 800-41 Rev. 1