Even if you have a wireless NIC that supports monitor mode, most Windows based wireless NIC drivers won’t allow you to change into this mode (WinPcap doesn’t support this either). You’ll need a little extra hardware to get the job done.
AirPcap (from CACE Technologies, now a part of Riverbed, http://www.cacetech.com/) is designed to overcome the limitations that Windows places on wireless packet analysis. AirPcap is a small USB device that resembles a flash drive, as shown in Figure 11-5. It is designed to capture wireless traffic.
AirPcap uses the WinPcap driver discussed in Chapter 3 and a special client configuration utility.
Figure 11-5. The AirPcap device is very compact, making it easy to tote ...