Workbench WiFi

Affordable 802.11ac 4×4:4 packet capture device

Performing an 802.11 packet (frame) capture from a AP is nothing new. But sometimes an extra AP isn’t available or there is a desire for a lower cost alternative. What looks like a wedge-shaped battle bot but can capture those 3×3 MIMO frames for $199? Why, this piece of heavy duty marketing… when running different software.

The WiFi Pineapple Tetra is one of my favorite inexpensive wireless tools, but it is limited to 2×2 802.11n at best. Installing a very recent build of DD-WRT on the Netgear R7800 allows for many of the same functions using an Atheros 4×4:4 802.11ac radio, albeit in a more primitive manner. Both iw and tcpdump are included in the base DD-WRT environment, so the usual commands for gathering basic site survey information and performing packet captures are available immediately. I do not have any USB storage devices fast enough to store a real time 300+ Mbps (37.5+ MB/s) capture, but the R7800 does have 512 MB ram, about 400 MB of which is free, so I generally capture as much as 350 MB to the /tmp ramdisk first and later copy the pcap to an external storage device. I can post some more detailed instructions if there is interes


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