The Three Essential Wi-Fi Troubleshooting Tools

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 titles and he has money.  The Rock now only wrestles if it's going to be memorable, thus adding to his legacy.  In the IT world, an example would be a guy I know [Hi Stuart, if you're reading this] who has owned a company, made a lot of money and now does regular trips to Africa to do IT work for Doctors Without Borders.  Maybe someday I'll reach the Legacy stage, but judging by the fact that this is my first blog in TWO MONTHS, I am not so sure.)  It could be that I have developed an ironic appreciation for clickbait.  Who knows?  


Whatever the reason, the bottom line is that I am going to make this here clickbait MEANINGFUL.  I want this blog to sit in the narrow zone of the Venn diagram where clickbait and useful information overlap.  And if I am successful, then you, the guinea pigs in this experiment, will get some good info about troubleshooting.


The first rule of Wi-Fi troubleshooting is DON'T TALK ABOUT WI-FI TROUBLESHOOTING... at the controller (or AP or management system).  Controllers, APs and management systems simply aren't going to be able to solve the really difficult Wi-Fi problems.  I know that some people will react negatively to that statement, but I'm in the Money stage (I think).  I don't care.  I know that controllers and management systems rely on information from APs.  I know that APs are unable to see the same radio frequency (RF) that Wi-Fi devices see.  I know that solving difficult Wi-Fi problems requires getting RF information around devices, not APs.  So, I don't want to hear it.  Save the pitch on how your controller/management system/AP can do troubleshooting for someone who doesn't know any better.  I only care about making your Wi-Fi work, and you're going to need to leave your desk to do that.


Now, with that out of the way, let's discuss the three tools that ARE useful for Wi-Fi troubleshooting. They are:


1. A production device with Discover/Scanner software installed.  (I'm going to call it Discovery software from here on out, just to try to make things simple.)


2. A laptop with Spectrum Analysis software installed.


3. A laptop with Protocol Analysis software installed.  (Which can be the same laptop.)


That's what you want.  Now, here are your options:


Discovery software


Windows: Acrylic WiFi is free, and it is the tool that I use when running Windows.  Metageek inSSIDer is a popular Discovery tool that costs $19.99 (all prices are going to be in USD).


Mac OS X: WiFi Explorer is $14.99, and I like it because it has some advanced features.

Wireless Diagnostics is native to Mac OS X, so you actually don't need to install Discovery software if you are troubleshooting Wi-Fi that primarily services Apple laptops and desktops.

iOS: Airport Utility is free, but you need to install it from the App Store.  You also need to enable the Wi-Fi Scanner function (see below) in the Settings for Airport Utility.





Android: WiFi Analyzer is free and it is great.  Just make sure you get the WiFi Analyzer from "farproc".  The Google Play store is less tightly regulated than Apple's App Store, and thus some charlatans have been allowed to create garbage apps called "WiFi Analyzer" in an attempt to leech off of the popularity of farproc's WiFi Analyzer.  (And I'm going to keep it non-judgmental by not mentioning which country these imposter apps seem to all be coming from.)


Spectrum analyzer


Mac OS X: Metageek's combo of Chanalyzer for Mac (a software product that is end-of-life'd, but still available for free) and a WiSpy USB adapter (I recommend using the WiSpy 2.4x because it's only $200, whereas the more popular WiSpy DBx is $500).


iOS: Oscium WiPry-Pro is a $199.97 lightning adapter that works with free WiPry software from the App Store


Windows: (Before I get to the Windows options, I have to mention that both of the aforementioned spectrum analyzers are limited.  For professional work, I recommend a Windows-based spectrum analyzer.)  I've come to like AirMagnet Spectrum XT, which is a USB/software combo that costs $3,395.  Previously, I was using Metageek Chanalyzer 5, which costs $349 (though there are a few Chanlyzer add-ons for building reports that might increase your price).  Chanalyzer 5 requires a WiSpy (either 2.4x or DBx) USB adapter.  Also, if you want to go El Cheapo, you can find Chanalyzer 4 -- a free version of Chanalyzer -- in Metageek's software archives.


Protocol analyzer


Mac OS X: Wireshark (free) with Airtool (also free!) is the killer combo here.  I avoid Wireshark for professional Wi-Fi troubleshooting because other products are far less time-consuming, but man if the Wireshark interface ever got more wireless-friendly, this could be dynamite.


Linux: Wireshark, though you'll need a Wi-Fi adapter that supports monitor mode.  Many internal Wi-Fi adapters on laptops and desktops do, in fact, support monitor mode, but not all.


Windows: AirMagnet WiFi Analyzer Pro is $4,115, but you can pair it with Spectrum XT for $7,250 for a $260 "savings".  (I put "savings" in quotes because when certain people I know go to the Nordstrom anniversary sale and tell me how much money they "saved", it seems that the total expenditure is always an eye-popping amount.)  You'll also need a Wi-Fi adapter that can capture into AirMagnet.  I use the Proxim 8494 USB adapter, which is $99.99.  If you need 3-stream capture (which, honestly, most enterprises don't because most devices support 1 or 2 streams and even the 3-stream devices usually use 1 or 2 streams even when connected to a 3-stream AP [how's that for a run-on sentence?]), then the AirMagnet 3x3 ExpressCard adapter can be had to $283.99.  OmniPeek (from Savvius, who used to be called WildPackets) is another great option, but it's really for hardcore frame analysis, whereas AirMagnet is for general troubleshooting.  OmniPeek Pro, which has everything you need for Wi-Fi troubleshooting, is $2,495 and OmniPeek Enterprise, which adds a few features that may be useful for wired network troubleshooting, is $4,995.  You'll also need a Wi-Fi adapter for capture, and the best choice for OmniPeek is the OmniWiFi USB adapter, a 3-stream adapter which runs $99.


PURPOSELY OMITTED: Site survey software


Site survey software is often cited as a troubleshooting tool, but I find little use for it.  In fact, I've often found it to be counter-productive when troubleshooting.


Site survey software allows a Wi-Fi adapter to do the same thing that its doing when running Discovery software (recording RSSI [received signal strength] while connected) or Protocol Analyzer software (recording RSSI while capturing in monitor mode) while placing that information over a floorplan to create a "heat map".  Cool!  Right?  You can just walk around with site survey software and really visualize where you have good coverage or bad coverage or too many APs or APs on interfering channels or whatever.


The problem with site survey software is that it doesn't use a production device when recording RSSI.  And (this one's important, so I'm going to really, really emphasize it) recording RSSI from a non-production device is MISLEADING and, thus, COUNTER-PRODUCTIVE.  (If it seems that I am over-sensitive about the subject of site survey software, it's because I am.  I work as a consultant, which means that there is always a natural period of mistrust where the client is trying to make sure that I know what I'm talking about and that I won't mess up his/her Wi-Fi.  Site survey software often fosters even MORE mistrust because it can make people think that their RSSI is one thing [the number that shows in site survey software] when it is actually another [the number that an ACTUAL DEVICE is showing].)  So, yes, site survey software is cool and useful for surveying BEFORE the Wi-Fi is installed, but it's really not a troubleshooting tool.


There you have it.  When you put together your Wi-Fi Troubleshooting toolkit, have those three tools: discovery software, protocol analyzer and spectrum analyzer.


Next time (which will be in a lot less than two months, I promise), I'll start talking about how to USE those three essential Wi-Fi troubleshooting tools.



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Comments

  1. Great post! I would add the fluke aircheck, just a really handy tool to get started. I'm not much of a Mac user, so I really appreciate that you listed the various os options.

    ReplyDelete
  2. Great post! I would add the fluke aircheck, just a really handy tool to get started. I'm not much of a Mac user, so I really appreciate that you listed the various os options.

    ReplyDelete
  3. Ben, Great article! "recording RSSI from a non-production device is MISLEADING and, thus, COUNTER-PRODUCTIVE" nails it! the client device perspective needs to be part of the design.
    I agree with TJ about the AirCheck. Its' ability to tune 802.11 parameters is huge.
    I would add Kali Linux to the list - It runs great in a VM and supports many Wireless USB NICs

    ReplyDelete
  4. TJ: Thank you. I have heard great things about Fluke AirCheck and it looks like it has a lot of cool features. The only thing I worry about is the connection testing feature. I worry that it is too dissimilar from the connection behavior of smartphones and other devices.

    wifistrong: Thank you. I am kind of a Linux novice, but that is good info about Kali Linux.

    ReplyDelete
  5. Replies
    1. No spectrum analyzers or protocol analyzers, to my knowledge. Meraki used to have a browser-based Discovery tool but I'm not sure if it still exists.

      Delete
  6. RE: Proxim 8494 on Amazon...looks like it's been discontinued because only 3rd party sellers are listed at $200.

    ReplyDelete

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