Sniff Wi-Fi

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...

The hot topic in WiFi nowadays is high density (HD), and for good reason.  It seems you can't swing a dead cat anymore without hitting some place (concert hall, convention center, tourist trap) where there's an attempt to offload cell phone data onto a WiFi network.  The most interesting thing about HD WiFi to yours truly is that it's the same fundamentals we've always known about, just recycled. If you were one of the lucky (unlucky?) ones to work in WiFi during its more formative years, you may have been taught certain basic concepts about WiFi.  For the author, fond memories still remain of sitting an Enterprise WLAN Administration course way back in 2003 (taught by noted Massachusetts Yankees fan David Westcott ) as part of my preparation for the certified wireless network administrator ( CWNA ) exam. What did Mr. Westcott teach us lo these many years ago? Plan out your space alternating between channels 1, 6 and 11 in the 2.4 GHz band. If APs are spaced t...

Yay, a new iPhone!   So sayeth me, my relatives (one of whom will receive my old iPhone), California (who will receive 8.75% in sales tax on the FULL UNLOCKED PRICE of the phone because California has a ludicrous sales tax law that taxes the pre-discount price of mobile phones) and anyone else who has been waiting for the iPhone to finally support 5 GHz WiFi.   But wait, there's more.  The iPad has long supported 5 GHz 802.11n WiFi, but the iPhone 5 does the iPad one better.  How?  Read on, amigos. Though Apple's most popular iOS device, the iPhone, has eschewed 5 GHz WiFi until iPhone 5, iOS-based access to 5 GHz channels (numbered 36 through 165) has been available in every iPad model. The iPad has always been 802.11n, which is good.  But the WiFi adapter in the iPad has always supported the bare minimum 802.11n , which is bad.  (Specifically, 65 Mbps Data Rate bad.)  This meant that an iPad is going to take about three times as much cha...

WildPackets OmniPeek has long been my favorite WiFi sniffing software, but lately this blog has been short on posts about it.  That needs to change.  So today I start a multi-part series (number of parts to be determined) on how I use OmniPeek to help me plan for and troubleshoot mobile devices. Mobility (defined here as seamless roaming between WiFi access points [APs]) is a longstanding enterprise WLAN issue that has kind of taken a back seat to supporting personal devices (a.k.a. BYOD).  For many enterprises, mobility remains important.  Car dealerships with push-to-talk handsets, warehouses with barcode/RFID scanners and retail locations with point-of-sale terminals are all examples of locations that require user devices to move around a large area without dropping connections, losing speed or experiencing choppy service. The solution to supporting mobility is to make sure that APs have adequate overlapping coverage without interfering.  It sounds simpl...

Oh, those darned iPhones. Can't live with 'em, can't keep your job without 'em. The vagaries of iPhones and other station devices are the most difficult part of managing a WiFi network, but there are some things that can be done on the infrastructure to try to make your stations work better. One of those things is lowering your AP transmit power to a level that more closely matches your client station's transmit power.  My main man G.T. Hill (of Ruckus Wireless ) recently wrote a blog post discussing why this post is bullshit. Now I'm going to tell you why his blog post is bullshit. (sorry, G.T.) G.T.'s primary point is that is is borderline mentally handicapped (politically correct term) to turn your AP's power down. His theory is that even if your client stations transmit at low power levels, having a high AP power level at least allows the from-AP data rates to stay as high as possible. (G.T. goes on to add that most traffic is downstream, th...

You say you like WiFi Sniffing? And having fun? And not succumbing to a painful demise due to liver sclerosis? Well, then there's only one product pronounced eye-pee-ay for you: Metageek's new visual protocol analyzer, Eye P.A. Amid all of our divisions over race, gender, religion and whether the Champions Bowl is going to be better than the Rose Bowl, we can agree one one thing: products named after alcohol are great . So you can imagine my excitement when I was made aware that Metageek -- hero to Windows users , villain to Mac users  and tease to iPad users  -- had introduced a WiFi sniffer. Metageek is known 'round these parts ("round these parts" being, "in my opinion" ) as being a proprietor of low cost, attractive WLAN analysis tools. InSSIDer is the best active site surveying utility I've seen for Windows. The WiSpy/Chanalyzer combination is my spectrum analyzer of choice. (And I'll just choose to ignore the iPad tease that has been...

You're never gonna sniff again Faulty packets got no meaning Though it's easy to pretend I know I'm not a fool Oh, how I want to sing those lyrics . To whom, you ask? Why, to Cisco Clean Air access points. Also, AirMagnet Enterprise sensors, Aruba Air Monitors and anything else that offers me a careless whisper worthless capture. Unlike WHAM! , distributed WLAN analysis is in. It seems that nowadays I can't swing a dead cat without hitting someone who is proud as punch of their system of distributed sensors that does something (spectrum analysis, intrusion detection, frame capture) cool. Distributed sniffing (meaning frame capture) or spectrum analysis does have its uses. If you need to find a rogue AP, identify a denial of service attack or get a general overview of your RF environment, systems like Cisco CleanAir, Fluke AirMagnet Enterprise and Aruba AirWave RAPIDS can all be useful. The problem is that these products are often used for more than that. An...