Sniff Wi-Fi

Do you own, manage, or provide technology services for a classy hotel?   Yes??   Then this blog's for you.   No, we are not going to reveal the secrets of luring wealthy clientele via watered-down booze and disreputable ladies.  Those things are obvious, and if they're not obvious you should ask a French person.  (One of my best friends is French, so I can say that...  I think.)   We are going to reveal how to quickly validate your other most important service -- Wi-Fi -- using free, built-in Mac software. The nice thing about providing Wi-Fi service at an upscale hotel (or other hospitality environment; convention centers, cruise ships, et al. count too) is that wealthy people hate to complain.  (Publicly, that is.  Privately that's all they do.)  The not-so-nice thing is that wealthy people are big fans of ghosting.  They will abandon your upscale hotel with the quickness if service of any kind dips below an acceptable level.  That includes the Wi-Fi. Luckily

I defend Apple a lot.  When Network World wrongly accused  the original iPhone of flooding Duke University's network, I defended Apple .  (It was later found to be a Cisco problem.)  When a health care provider I was doing some work for blamed SIP-enabled iPhones for a VoIP problem, I eventually found out that the APs were to blame .  (The APs were failing to respond to WiFi frames tagged as "Background" QoS.)  Time and time again networking folks blame device makers like Apple, and time and time again the problem ends up being the network. There are times, however, when it really is Apple's fault.  When the network is operating just fine.  This is one of those times.  The problem is that I just don't know why. 802.11n (HT) and 802.11ac (VHT) networks operate in co-existence with first generation (802.11a/b/g, that is) WiFi a lot.  When that happens, the HT or VHT access point operates in mixed mode. There are all sorts of ramifications when a WiFi network

Yours Truly has been worried about the future of WiFi sniffing.  Yours Truly worries about the people (they seem to prefer site surveyors) the software (AirMagnet has yet to support 802.11ac adapters) and the methods (WildPackets has been pushing AP-based capture).  To a person who believes that portable WiFi sniffing is essential for optimizing WiFi performance, it is all very disconcerting.   And yet, there is hope.  WiFi sniffing is ready to step into the 802.11ac/Internet of Everything era, and here is how it can be done. WildPackets OmniPeek has long been the author's favorite WiFi sniffer, but it only runs on Windows.  For years and years and years that was fine.  There were always a few Windows-compatible WiFi adapters that worked great with OmniPeek.  Now, however, WildPackets has gone in a different direction.  They are promoting WiFi sniffing via an AP (which often results in a worthless capture ) and saying that they don't expect USB-based capture to be viable

A year ago yours truly wrote about the importance of device location when capturing Wi-Fi frames in a post titled, " Worthless Capture ".  Well, recently another Wi-Fi sniffing bugaboo has become more prevalent: devices that lack the physical capability to capture a  data frames. This whole problem really stems from 802.11n.  As many people (including the author) found out when the iPad was released in 2010, not all 802.11n devices have the same capabilities .  That is an annoyance to consumers, but it's downright dangerous to Wi-Fi professionals.  Most Wi-Fi networks require sniffing at some point (for surveying, for event preparation, for troubleshooting, etc.), but most Wi-Fi sniffing devices are incapable of sniffing high rate data frames. One more time: Most Wi-Fi sniffing devices are incapable of sniffing high rate data frames. The Linksys WUSB600N, which yours truly uses to sniff with WildPackets OmniPeek?   Only 2 radio chains (a radio chain is a transceive