Keith Combs' Blahg

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Wireless Network ID's and the Joys of Cartoons

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Red Axe by Hugh at gapingvoid.comLast weekend was typical.  I was preparing for a couple of seminars for this week on some pretty intense topics.  The wireless security session I delivered today was attended by some influential IT Pros from around the Dallas/Ft. Worth metro area.  I also had the pleasure of having a number of people from the United States Secret Service and the Federal Bureau of Investigation.

There’s more to this story…

My preparations for these types of session usually involve research, printing, unpacking or uncompressing archived content, tests, etc.  It’s a long process and eats time.  Fortunately, uncompressing a huge virtual machine leaves time to multi task.

So I was surfing some of my favorite internal distribution lists.  Someone posted a link to a blog post from gapingvoid.com.  There was an excerpt from the blog and it’s obvious from what I’m reading that someone is pretty pissed off at Microsoft.  I didn’t recall at the time anything about gapingvoid.com, but I did notice the cartoon style.  I had seen those somewhere.

So I followed the link to Hugh’s blog and dug around a bit.  It was already March 5th so I noticed there was a newer and more pointed post.  Hugh had posted a challenge, so I figured I’d respond and see what happens.  He didn’t really notice my first comment, or he probably ignored it because it was the typical Nick Burns the Computer Guy style post.  Someone inside my company mentioned it may not be apparent I was offering to help to I blasted off a quick email directly to the gapingvoid.com email address.

Hugh called me back in five minutes.  We talked briefly and he wanted me to use Skype to call him back.  So I downloaded the software, grabbed a headset and five minutes later I was talking to Hugh Macleod in London from my palacial Texas ranch.  You’re allowed to say that if you have an acre and can at least hear a cow or horse nearby.  One of the reasons I wanted to help was because I liked the picture in the post at http://www.gapingvoid.com/Moveable_Type/archives/002369.html although the Red Axe picture probably expressed his frustration better.

We messed around for a bit and compared the drivers and software he was using to the way I am setup.  It so happens that two of my laptops use the same Intel wireless chipsets as his tablet pc.  That was pretty much a waste of time because we didn’t spot anything apparent.  I then started to ask some of the key questions that helped determine at least one fix.  We got one of his components, a D-Link wireless bridge to reset and start providing a wireless network signal.  Hugh was happy.  I didn’t really know all of this until later because you see, there’s a small time difference between London and Dallas.  Hugh needed to crash and get some sleep, and I needed to cook for my family.  So I typed up some instructions and shot them of via email.  I checked my smart phone the next morning at 6am to see if there was a black cloud or nuclear mushroom cloud cartoon waiting for me…  Fortunately my instructions worked and he was a happy camper.

I got another email Thursday and apparently his wireless is down, again.  There are a number of possibilities left.  He could be cooking some popcorn in a microwave oven and cooking his signal at the same time.  The 2.4gHz spectrum is crowded with interference and his access point uses that spectrum.

It could be that because we reset the wireless bridge to default settings, the name the bridge is broadcasting is also used by another wireless access point in the area.  This can wreak havoc because it is assumed that the access points are on the same network.

It could be a number of other possibilities like:

  1. Is there a radio on/off switch for wireless on the machine? Is it on? Is a keyboard combination causing the wireless card to turn off? 
  2. Is the adapter enabled?  I know it is supposed to be.
  3. Is there any network interference? 2.4Ghz phone? Microwave?
  4. Is the wireless adaptor properly waking up after a suspend or hibernation of the tablet?  This could be tested by only shutting the machine down when not in use.  I would not use suspend or hibernate for several days to rule that out.

We’re going to change the SSID (network name) as soon as I can get in touch with him Friday or Saturday.  Any suggestions?  How about darkcloud?

I started this story talking about wireless security, my session on Thursday with the feds in the room, and the email's I got.  Sorry, I could tell you about the session, but I’d have to shoot you.  I’m teasing of course.  You can see the session I delivered in April and I promise to add a bunch of stuff I learned from the federal agents.

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  • My hunch would be interference from another device.  You already mentioned the microwave, but there's also cordless phones and - of course - other wireless devices.

    Most consumer-grade wireless devices default to either channel 1 or 6.  Along with changing the SSID, you can also change it to another channel.  If memory serves, the EU has a few more channels than the US.

    Of course, the better option would be a site survey.  Depending upon his computer, the wireless drivers might have the ability to scan the airwaves for other wireless networks and this may be enough.  Another option is to download Netstumbler.  If he has a compatible card, then he should be able to find the channels of other WLANs.  Obviously, his WLAN should be on a different channel.

    As for which channel...well, although most people in the US believe that you can only use channels 1, 6, and 11 in reality you can choose any channel.  Channels 1, 6, and 11 are the just ones that don't overlap each other, but a WLAN on a channel other than those three will work even if there is another WLAN close by with a channel that overlaps.  

    For instance, at home I'm surrounded by WLANs on the regular 3 US channels.  Adding another to the mix is not an option, so I set my WLAN to channel 9 and I've never had a better signal.

    --
    Chad

  • Yea, thanks for that and I agree.  Hugh and I will be trying a few things tomorrow.

  • Hugh and I messed around a bit more this morning.  He doesn't have a wireless phone and there are no microwave oven's nearby.  The D-Link WAP works but during the course of a 40 minute session this morning, the wireless connection got dropped and restarted about four times.

    We reviewed the Intel 2200bg card properties and he is set in the same manner as I am.  All of his settings are the default for power management, trasmission strength, etc.  They are using channel 11.

    He's headed off on some travels next week so we'll see how the tablet performs at the conferences and coffee houses he uses.  If he comes back and says he had no issues, then the evil red axe may fall on the poor little D-Link bridge.  We'll have to film that.  :)

  • I am interested in that wireless security story! :->

  • Interesting...I have a D-Link DWL-2100AP and it works like a champ.  I even used it as a wireless client for a while before I broke down and pulled some CAT5 - just to make sure I wasn't dying so much because of a network delay.  (Conclusing: nope, I just suck that much, but I am getting better at sticking 'nades.)

    One thing you haven't mentioned - or at least I haven't understood it correctly if you have - is the A/P dropping the connection or perhaps rebooting.  It could be that he has a defective A/P.  Is he able to physically see the A/P during one of these drops?


    --
    Chad

  • Yes, the access point is in the same room so Hugh can see it.  We he gets back in town, we'll see what "corrective" action needs to take place next.

    I'd love to chop that sucker in half with an axe.

    I am planning the same demise to a laptop hard drive I have.  I plan to do a Windows Vista backup and recovery screencast soon.  Part of the demo will be destroying the original hard drive.  Any destruction ideas?

    I was thinking of burning rubber on it with my Harley or taking a hammer to it.  Of course, I could also drown it in my pool.  We'll definitely have some fun with it.  Channel9 quality stuff for sure.  :)

  • One wonders what the LEDs are doing during the outages.  Obviously, if they all go out...

    As for the hard drive, 16p (or larger) nail would do it.  Too bad you couldn't do something a little more Halo-esque.

  • Said by Chad, "Too bad you couldn't do something a little more Halo-esque."

    Uh, my plasma rifles and energy sword are completey charged.  :)

    LED checks are a good idea.  Hopefully this turns out to be a bad wireless bridge since they are pretty cheap and easily replaced.

    The saga continues...

  • I'll take the things that go BOOM!

    (Oh, this could easily turn into a very long Halo thread.)

    --
    Chad

  • For another data point.. I have a DLink DI-514 and it goes away about every hour or so.  Just for about 5 or 6 seconds but it's enough to really annoy me.  That'll be the last time I pay $20 for a wireless router... :-)
    I see this on all my pcs with 2 different USB wireless adaptors (1 DLink USB and 3 Dell 1390s) so I'm pretty sure it's the router that's doing the lan-nap.

  • PingBack from http://blogometer.com/2006/03/15/mirthful-microsoft/

  • UPDATE: I checked with Hugh on his travels in Europe this week.  Before he left for that trip, I asked him to keep an eye out and see if he had any flaky connections at the various locations.  He reports back that the tablet has performed very solidly so it's looking like the bridge device at his house may be the culprit after all.  I recommended a replacement product from the a company I like.