Sniff Wi-Fi

Some days you wake up and say to yourself, "how can I be more like Buzzfeed ?"  Buzzfeed is popular and beloved and has an office across the street from a great Mexican restaurant.  I have a few friends and wonderful parents, but I can barely cook a taco.   What is it that I'm missing (besides venture money, a flock of ambitious MBAs and universal scorn from the intelligentsia)?  Lists!  That's what I'm missing.  Hit-trawling, crowd-pleasing lists! So here it is: the first in what hopefully will be a series of one.  A list of Three Simple Ways to Boost Your WiFi.  #LOL #cute #OMG #trashy 1) Add an 802.11n/ac USB adapter to old 802.11a/b/g laptops and desktops. Some folks in the WLAN business like to use the term "5G" to refer to 802.11ac, but I refer to 802.11a/b/g as 1st generation WiFi and 802.11n/ac as 2nd generation WiFi.  The reason I do that is because big improvements to power consumption, receive...

People who do WLAN analysis agree that filtering is a part of sniffing WiFi frames/packets.  More information can be extracted from captures when the focus is on one AP or station or protocol (or a combination of same).  Where people disagree is on which type of filtering is best: capture filters or display filters?  Yours truly is a capture filter man, and some iPhone analysis was a reminder why. Filtering 802.11 captures is covered pretty well in the CWAP Study Guide (of which I am a co-author).  A capture filter extracts frames before  they are captured.  The only frames captured are the ones that match the filter.  A display filter extracts frames after  they are captured.  Every frame is captured.  Then the filter is applied so that only frames matching the filter are shown in the protocol analyzer.  To use the example of a filter on my iPhone, if a capture filter were used then all of the frames from all of th...

Fear not your sniffers, dear WiFi folk.  For they are your path to the truth. I had a conference call today and the topic of carrier devices (smartphones, 3G/4G enabled tablets, etc.) on Wi-Fi networks came up.  The person on the other end needed to make sure that his WiFi devices were optimized for a variety of different WLAN infrastructures. My first reaction (as is my first reaction to most WiFi related topics) was to sniff.  First set up the infrastructure.  Then use the device (which could mean connecting, roaming or running an app).  Then sniff what's happening.   His reaction to my sniffing idea was pretty negative.  Their testing procedures are basically trial & error.  Set up the WLAN, then connect the device and then document what the user experience is.  If the user experience stinks, then make a change.  He was a sniffophobe. I get why people are sniffophobes.  WiFi sniffers can be expensive and diffi...

A year ago yours truly wrote about the importance of device location when capturing Wi-Fi frames in a post titled, " Worthless Capture ".  Well, recently another Wi-Fi sniffing bugaboo has become more prevalent: devices that lack the physical capability to capture a  data frames. This whole problem really stems from 802.11n.  As many people (including the author) found out when the iPad was released in 2010, not all 802.11n devices have the same capabilities .  That is an annoyance to consumers, but it's downright dangerous to Wi-Fi professionals.  Most Wi-Fi networks require sniffing at some point (for surveying, for event preparation, for troubleshooting, etc.), but most Wi-Fi sniffing devices are incapable of sniffing high rate data frames. One more time: Most Wi-Fi sniffing devices are incapable of sniffing high rate data frames. The Linksys WUSB600N, which yours truly uses to sniff with WildPackets OmniPeek?   Only 2 radio chains (a radio chain ...

Sometimes I dream That he is me You've got to see that's how I dream to be The dream I riff, the dream I sniff Like Nate I want to be like Nate (Silver) Much has been made of the increased emphasis on statistical analysis, especially in the wake of New York Times blogger Nate Silver correctly predicting the electoral results for all 50 states in the recent United States presidential election.  Can analytics be applied to WLANs?  Of course they can.  It's just a matter of sniffing the right stuff. There are a lot of bad WiFi networks out there. There.  I said it.  It's out there and I can't take it back.  I see a lot of Wi-Fi in my travels.  Almost all of it could be improved upon and much of it seems like it was installed by folks with little understanding of how 802.11 networks work. So, what do we do to fix it? We can have best practices.  We can finally ditch automatic RF controls.  (Please, people.  If you haven't h...