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Wi-Fi Network Monitoring Tools?
Brian the Wise asks: "For all of you with large and/or complex wireless networks out there, what tools (commercial or otherwise) do you use to keep an eye on the health and state of your network? I'm not only interested in the security/IDS side of things, but also bad packets, reflections, clients flip-flopping between APs, etc. I've looked at all the usual open source projects, and so far Kismet comes the closest to my needs, but the wireless drivers on Linux do too much sanitizing of packets so I never see the bad ones. I know the FreeBSD drivers show more, but some of the advanced stuff (ie extra info from the Cisco Aironet drivers) is not supported by tcpdump or ethereal. Is there anything I can do besides getting up close and personal with the Linux network stack and drivers?"
What is the best, high powered 100mw-200mw, high sensitivity receiver pcmcia/pccard adapter you can buy that works great with Linux? External antenna ports are a plus.
I have looked at the Senao 200mw cards and am thinking about buying one, good or bad choice?
I did a pretty thorough review of a bunch of (Globespan-Virata, nee Intersil) Prism chipset-based cards for my new startup just a few months ago, and the Senao is far and away the best, although the ubiquitous and very inexpensive Netgear MA401 was surprisingly good for the money, among lower-power cards. (I've heard some people say they don't like these, but I own several, purchased at different times, and all seem better than the average of other Prism-based cards. YMMV.)
The thing that makes the Senao cards great, surprisingly, isn't its high-power transmitter though (other companies offer those, too), but rather the fact that Senao's engineers were sharp enough to realize that a better transmitter doesn't really do much good without a better reciever to go with it.
The receiver is the weak spot in most Wi-Fi cards, and better performance here *really* pays off in the real world, which is why there are so many Senao fans among those building wireless setups that *need* to work.
FWIW, I think external antennae are a PITA if you're moving around, none of the tiny coax connectors are really going to stand the large number of mating cycles required to remove and reinstall the antenna everytime you relocate your laptop. If you really have to have the exteranl (for instance, if you plan to use it in a fixed installation in the future), you can get the compact "vampire tooth" antennae to snap into the Senao's MMCX connector from Netgate.com. (No connection, other than as a happy customer and friendships with the owners from when they lived here in Austin.)
These comments apply only to Senao's 802.11b Prism-based products. Their newer cards are based on chipsets from other vendors (Atheros Mercury for 802.11b/g, among others) , and I've heard those are not nearly so superior to their competition. (Not to mention you have to decide if Broadcom is right in thier claims that Atheros violates the spec., thus "poisoning the waterhole" by slowing other vendors' 802.11b radios in the vicinity to a crawl. I don't know if this is real or not yet, but anecdotal evidence seems to support it, although I don't use G myself...)
"The future's good and the present is nothing to sneeze at." - Roblimo's last
Yeah, because people love explicitly setting up every tcp connection they use.
One day someone will have to teach slashdot readers the meaning of the word "transparent" and why it's important.
-j