Numerous attacks using duplicate packets, changed packets, or out-of-order packets are able to successfully evade and pass through the Cisco IPS appliance
when it is operating in inline mode.
What could be causing this problem?
A.
The IPS Application Inspection and Control is disabled.
B.
All the DoS signatures are disabled.
C.
All the reconnaissance signatures are disabled.
D.
TCP state bypass is enabled.
E.
The normalizer is set to asymmetric mode.
Explanation:
http://www.cisco.com/en/US/prod/collateral/vpndevc/ps5729/ps5713/ps4077/white_paper_c11- 459025.html