Sniff Wi-Fi

802.11ac is the latest and greatest WiFi standard, but it's confusing.  So many questions: Is it really that much faster than 802.11n? (It can be.)  Is it worth upgrading?  (Probably not in the enterprise, but at home, absolutely.)  How fast is my device?  (Data rates as low as 6.5 Mbps and a high as 1.3 Gbps.)   Getting specific answers to 802.11ac performance questions can be a chore sometimes, but there's a simple way to check your APs.  All you need is a wireless sniffer and about five minutes. Today I wanted to find out what my 802.11ac AP is capable of.  I suppose I could've gone in search of a data sheet, but instead I decided to break out the wireless sniffer.  It was a quick and simple process. Step 1: Find the channel of your AP If you're a Mac OS X user, you can use Wireless Diagnostics .  If you use Windows, then Acrylic WiFi is probably your best option. My channel was 48. Step 2: Capture on your channel  ...

Spec-ing the Layers with WiSpy (one time, one time) Channel gone red with this stream (two times, two times) Killing my channel with this song Killing my WiFi With this song Taking my WiFi With this stream Killing my WiFi With Bluetooth spe-ee-ee-eeakers... Wireless streaming (music, video or, in the case of the wonderful song referenced above, a music video ) can sure kill a WiFi connection.  It's good to have a spectrum analyzer to identify the problem.  It's even better to remember to use it. Wireless streaming devices are popular nowadays, but most of them are benign.  An AppleTV, for instance, can wirelessly stream audio and video or it can act as a mirroring device for whatever audio or video is on your smartphone, tablet or laptop.  (And mirroring is tougher on WiFi than basic streaming.  When I mirror my iPhone 5, I'm creating three streams.  One from my wireless router to my phone for the Internet stream, a second from my phone back ...

Chatty smartphones have been an issue for years.  Whether you're concerned with security or performance  (or both), the amount of Probing being done by unconnected iPhones, Galaxies and the like has been worrisome.   Today, things have changed.  Smartphones don't Probe as much.  This is probably for the better, but there could be a catch. I'm an Apple guy.  Even when I was using PCs in college (things were different back in the 90's , I tell ya), it was always because they were free.  Once I finally had to buy a computer, I went straight to the very first iBook in 2001.  I own an iPod, iPad, iPhone and MacBook Air.  My next computing purchase will probably be an iMac (to better record those promised-but-not-yet-delivered online training videos on WiFi that I touted six months ago).  So, I like the company.  And I like bashing its competitors sometimes.  (Not my most magnanimous trait, but nobody's perfect.) I liked poi...

It's been over two-and-a-half years since yours truly last wrote about Oscium WiPry , but there is reason to today: they fixed it!  Now the only 2.4 GHz spectrum analyzer for Apple iOS reads signal level correctly.  And using the new, corrected version reminded the author why WiPry is a nice product at a reasonable price. The concept of a spectrum analyzer hasn't changed in decades, and for good reason.  It's simple.  A device listens for activity at a given frequency and displays a readout of said activity, usually in a fancy, colorful way. In the last two years, however, many things have changed about spectrum analysis for WiFi.  PC card slots have become increasingly rare, thus leaving the Cisco Spectrum Expert in the margins.  Sensor-based spectrum analysis has increased in popularity.  Metageek, makers of my favored spectrum analyzer , stopped offering free software with their signature WiSpy series of spectrum analyzers. What hadn't chang...

It's time to switch things up a bit.  WiFi sniffing is a fascinating topic and all, but good ol' Yours Truly wants to try something new.   This will be the first in the "Not Sniffing, but..." series on the Sniff WiFi blog.  I come across interesting topics outside of sniffing all the time, so I want to add short blog posts on some of these topics. Several months ago WLAN bon vivant Keith Parsons  posted a blurb on his WLANPros.com blog about the Fluke Networks LinkSprinter .  I contacted someone from Fluke Networks to ask about the LinkSprinter, and they were gracious enough to send me one to test. LinkSprinter is a wired testing tool.  It's more for people who install APs than for people who, like me, primarily do frame captures.  Still, we both do troubleshooting.  The LinkSprinter is definitely for troubleshooting. The tool is pretty simple.  You plug in an Ethernet cable, and you pre...

Two years ago tomorrow Apple introduced the iPhone 5.  It was a big deal.  It was a big deal for gadget folks who wanted a bigger iPhone.  It was a big deal for wireless LAN folks who wanted users to use smartphones with speedier WiFi.   Now the iPhone 6 has been announced and it appears to be more of the same.  Gadgeteers get their bigger iPhone.  Wireless folks get their faster speeds.  Problem is, the faster wireless speeds likely won't mean anything for high capacity wireless deployments. The big news about the iPhone 6 is 802.11ac.  Yippee!  Apple has finally adopted the latest and greatest WiFi standard in a mobile device. 802.11ac has data rates as high as 6.9 Gbps in the standard, but wireless LAN folks know that's not what happens in real life.  Real 802.11ac devices top out at a 1.3 Gbps data rate when multiple input-multiple output (MIMO) antenna systems are supported, while non-...

In the beginning, there was Coverage.  And so it was that 802.11 and his only begotten Son, WiFi were blessed upon PCMCIA cards who doth receiveth adequateth Coverage. And then as Coverage grew and the lands of Tablets wereth discovered, so came Capacity.  And thus did Capacity grow to represent all that was good and great about deploymenteths upon this fruitful land. And now, my Sons and Daughters, things have changeth again.   For Coverage and Capacity will both leave the Higheth of Densiteth WiFi wanting.  And so we shun them both.  For it is Neither -- Coverage nor Capacity -- that will taketh thy to the WiFi promised land. In case it was unclear, designing wireless LANs for Capacity has become an article of faith in some circles.  Keep it to 40 devices per AP.  Or 50.  Or 150.  Whatever the number is, the whole concept is misguided. WiFi uses radio frequency as its physical layer, and ther...