Sniff Wi-Fi

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 ( farproc ) Chrome

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 the A