In an effort to optimize WLAN performance ABC Company has already upgraded their infrastructure from 802 11b/gto802 11n. ABC has always been highly security conscious but they are concerned with security threats introduced by incompatibilities between 802.11n and 802.11a/g in the past.ABC has performed manual and automated scans with products that were originally designed for use in 802 11a/g networks.Including laptop-based spectrum and protocol analyzers as well as an overlay 802 11a/g WIPS solution.ABC has sought your input to understand and respond to potential security threats.
In ABC’s network environment, what type of devices would be capable of identifying rouge APs that use HT Greenfield 40 MHZ channels? (Choose 3)

A.
802.11n WPS sensor with a single 2×2 radio

B.
The company’s current laptop-based protocol analysis tools

C.
WIPS solution that is integrated in the company’s AP infrastructure

D.
The company’s current overlay WIPS solution

E.
The company’s current laptop-based spectrum analysis tools

Explanation:
HT GreenfieldThe Greenfield PHY header is not backward compatible with legacy 802.11a/g radios and can only be interpreted by 802.11n HT radios
Laptop Analyzer automatically identifies hundreds of performance problems, such as 11b/g conflicts, 802.11e problems, and QoS, as well as dozens of wireless intrusions and hacking strategies, including Rogue devices. With the Laptop Analyzer, users can classify and decode Non-HT (legacy), HT mixed format and HT greenfield format traffic and identify backward compatibility issues with legacy 802.11a/b/g devices operating in the same environment.
http://www.njbo.net/tools/Laptop%20Analyzer%20-%20WLAN%20Monitoring%20and%20Troubleshooting%20Tool%20-%20AirMagnet.htm
The HT Greenfi eld PHY header cannot be detected by a WIPS that is using legacy 802.11a/g sensors. The solution to this problem is to upgrade the WIPS with new sensors that also have 802.11n HT radios. (the company has already upgraded to 802.11n so C is correct)