Sniff Wi-Fi

The last Sniff Wi-Fi post; on why Wi-Fi professionals should stop disabling low data rates, was met some resistance.  Be it in the comments  or  on Twitter , several experienced Wi-Fi folks disagreed. All arguments in favor of disabling low rates  (the ones that were presented to me, at least) were refuted in the text of the Leave, Leave, Leave My Rates Alone blog post.  But text is a less accessible messaging method.  "A picture is worth a thousand words", as the old saying goes. If pictures will get the message across better, then pictures are what I'll use.  What follows is an illustrated look at why disabling low data rates is a bad idea. It's gauche to begin an illustrated work with text, but to understand the problem with disabling low Wi-Fi data rates one must first accept some facts about Wi-Fi devices (smartphones, laptops, etc.): 1. Wi-Fi devices -- not APs -- control associations and roaming. 2. Wi-Fi devices roam based on low rec...

Sometimes you have to return to the classics.  Who better than less-than-memorable pre-gangsta rapper Hi-C to take us there? Much like the cool kids have embraced the neon colors and late-night TV comedy of the grunge decade, so too has this blog decided to embrace its past, only with a twist.  Five short years ago I  wrote a plea asking that Wi-Fi folks stop disabling high data rates on guest networks.  And they did!  (For the most part.)  Unfortunately, the pendulum has swung too far.  Now it's time to ask Wi-Fi folks to stop disabling low data rates; or, to paraphrase Hi-C: leave my rates alone. Wi-Fi folks are always looking for ways to make wireless channels more efficient.  That is a good thing.  Wi-Fi's one limited resource is channel time, and so it is great to see more and more Wi-Fi people looking for ways to get the most amount of data across a channel in the least amount of time. Disabling low data rates is a relati...

Let's start by talking about what OnHub , Google's supercharged 802.11ac wireless router (made by TP-Link, actually) can not do. OnHub does not allow you to create multiple SSIDs.  Creating multiple SSIDs is nice because it allows a guest network to be created.  That way guests don't have to be given the Wi-Fi passphrase for the internal network.  (On the other hand, multiple SSIDs slow down Wi-Fi performance because each SSID has it's own set of Beacon frames.) OnHub does not allow you to choose your channel.  APs choosing their own channel often limits performance.  The best channel at a user's desk may be different from the best channel nearby the AP.  Usually selecting the best channel at the users' locations makes Wi-Fi work best.  (On the other hand, when the AP selects its own channel that means that the AP has the ability to change channels if a high-powered interference source is detected.) OnHub does not allow you to adjust AP transmi...

I'm giving a Webinar today at 11 am, Pacific Time on five common Wi-Fi problems and how I use AirMagnet to troubleshoot them.  NetScout (formerly Fluke Networks Enterprise), owners of the AirMagnet product line, is putting it on. You can register here:  https://www.brighttalk.com/webcast/5522/177567 Sorry for the late notice. If you miss the live Webinar, you can always access it later. *** If you like my blog, you can support it by shopping through my  Amazon  link.  You can also donate Bitcoin to  1N8m1o9phSkFXpa9VUrMVHx4LJWfratseU  or to my QR code: Twitter:  @Ben_SniffWiFi ben at sniffwifi dot com

Eleven months ago, I wrote about Fluke Networks' Ethernet testing tool, the LinkSprinter .  Now there's a new model, the LinkSprinter 300 , and Fluke was nice enough to send me one to test.   LinkSprinter 300 is basically the same as the LinkSprinter 200, except it costs an extra $100 and it has two extra features: one cool and one that I haven't tested. I really, really hate it when people say "read this" in the middle of a discussion.  It is sauce of the weakest variety.  Just frickin' summarize it.  People tend to give me the ol' "read this" either when discussing a topic that they've written about or in an attempt to cite evidence.  In both cases, a summary will do.  If you are discussing Wi-Fi sniffing with me on Twitter and you wrote a white paper saying that Wireshark is the bee's knees, then tell me why on Twitter.  If you believe that it wasn't a fact that the Earth is round until Greek philosophers proved it a few th...

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...