What session flag would be used if a packet is not being checked by IPS?

The correct session flag indicating that a packet is not being checked by IPS is "npd." This flag stands for "Not Packet Data," which signifies that the packet has bypassed the Intrusion Prevention System (IPS) checks. When a session is marked with this flag, it implies that the packet does not require analysis or inspection by the IPS due to configuration settings or specific policies in place.

Understanding the context of session flags is crucial in firewall management, particularly in identifying how packets are processed and the level of security applied to them. The usage of the "npd" flag specifically points to scenarios where performance or operational policies dictate that certain traffic should not undergo IPS scrutiny, possibly to preserve resources for other critical packets or to handle trusted traffic efficiently.

In contrast, the other flags like "nds," "log," and "npu" serve different purposes in the context of network performance and security monitoring. Knowing what each flag represents helps administrators make informed decisions about traffic handling and security enforcement in their firewall configurations.