Modular QoS Command-Line Interface (MQC) implements packet filtering.
An untrusted packet is a packet with potential security risks or is a one that users do not want to receive. The packet filtering function allows a device to directly discard untrusted packets to improve network security.
With MQC, a device is configured to identify untrusted packets and discard them, as well as identify trusted packets and permit them to pass through.
MQC-based packet filtering classifies packets more precisely than a blacklist, and is more flexible to deploy.