Sniff Wi-Fi

At the 2018 Wireless LAN Professional Conference (WLPC), I was scheduled to give a ten-minute "Ten Talk" on Wi-Fi surveying without using site survey software.  I aborted that talk at the last minute in favor of a talk on Ghost Frames .   After the WLPC, Matthew Norwood told me on Twitter that he was looking forward to the talk about surveying without using site survey software.  I don't want to disappoint Matthew, or anyone else who was looking forward to that scheduled Ten Talk.  Here, then, is a YouTube version of the aborted talk on Wi-Fi surveying without using site survey software: ****** If you like my blog, you can support it by shopping through my  Amazon  link or becoming a Patron on  Patreon .  Thank you. Twitter:  @Ben_SniffWiFi ben at sniffwifi dot com

I wrote about using Discovery software , and then it dawned on me: many people prefer pictures. Here, then, is how I use Discovery software when troubleshooting Wi-Fi, illustrated. First, I figure out which device needs troubleshooting.  In this case, let's pretend it's one or more iPhones. (That #nofilter picture was taken by me at about 4:50 a.m. on the morning of January 20, 2009.  It was COLD a.f. out there.) Notice how my iPhone shows RSSI instead of signal bars.   Your iPhone/iPod/iPad can , too. Once I know which device needs troubleshooting (and, PLEASE, do not skip that first step.  Troubleshooting without using the actual device that needs to use the Wi-Fi is a big waste of time that annoys users), then I need some Discovery software. iOS: Airport Utility (Apple) Mac OS X: Wireless Diagnostics (Apple), WiFi Explorer (Adrian Granados - $15) Windows: Acrylic WiFi (Tarlogic), inSSIDer (Metageek - $20) Android: WiFi Analyzer ( farpr...

Who wants some free stuffffffff?!? You're reading a free blog, so I'm guessing the answer is, "all of us".  And that's good.  You've come to the right place.  Because the first part of my three-part series on Essential Wi-Fi Troubleshooting Tools is going to be about the free (or, very inexpensive) one: Discovery Software. Discovery software, which is also called Scanner software, is software that records and displays information that a Wi-Fi radio gathers during 802.11 Discovery.  There are two ways that 802.11 Discovery can be done: Active Scanning and Passive Scanning.  (Hence, the term "Scanner" software.)  Passive Scanning involves a device listening for Beacon frames that have been sent by APs.  Active Scanning involves a device sending Probe Request messages as a broadcast in the hopes of getting APs to respond with Probe Response messages.  Beacon frames and Probe Response frames carry essentially the same thing: information about th...

Clickbaitttttttttt! "Three Essential Tools"...  Brilliant!  Years ago, I would've been embarrassed to have such a click-baity headline.  No longer. Why the change, you ask?  I don't know.  It could be that I'm in the Money stage of my career.  (You see, I relate most things in life to pro wrestling.  A pro wrestler's career has three stages: Titles, Money and Legacy.  When you're young and you don't know any better, you want titles.  Being " Intercontinental Champion " [or, in the case of an IT guy, " Network Administrator "] fulfills you.  Management takes advantage of that by underpaying people who are in the Titles stage.  Once someone reaches the Money stage, they are no longer impressed by titles.  "You want to make me Intercontinental Champion?  Great.  What's my paycheck?"  The final stage is the Legacy stage, which most of us never reach.   The Rock is in the Legacy stage.  He has won titl...

There is a dirty little secret in the world of enterprise Wi-Fi: auto-channel selection doesn't work very well.  Every wireless LAN vendor has it.  Every wireless LAN vendor promotes it.  But when the Wi-Fi gets busy or crowded of full of mobile devices, auto channels will leave users frustrated and admins confused.   What to do about enterprise auto-channel?  Why, fix it, of course.  Here are some tips for getting it fixed the right way. First, the positive side of auto-channel: it saves you time.  Auto-channel selection is one of the two primary parts of auto-RF protocols that are supported by enterprise controllers, APs and management systems.  (The other part is auto-transmit power.)  Auto-RF protocols automatically adjust channel numbers and transmit power levels on APs.  Auto-RF protocols use information received by a large number of APs to decide when to adjust.  What that means is that if an AP senses a microwave oven b...

Nine months ago (bad way to start a blog post, I know) I wrote a blog about the future of WiFi sniffing .  In the comments section (perhaps the only worse thing for a blogger to say), someone mentioned a free, Windows-based application called Acrylic WiFi .   I briefly checked out the app and dismissed it as yet another Discovery utility disguised as a something more.  Then I actually used Acrylic WiFi and...  it works!  It sniffs WiFi frames (sort of) and it does it for free (outside of the cost of an ordinary 802.11 USB adapter)!  This changes everything (kind of)! For years, the method for free WiFi sniffing on a Mac has been simple.   Head down to the bottom of this post for a reminder. Now, we can do similar things in Windows.  It's not quite as simple and it's not totally free, but it works (pretty much). 1. Download and install  Acrylic WiFi Free , including Monitor Mode support (and, actually, if you can find an ol...