[clue-tech] Coffee shop wireless connection problem

[Dennis J Perkins]

Matt Gushee wrote:
> Dennis J Perkins wrote:
>
>>> Anyway. What I am most interested in at this point is 
>>> troubleshooting techniques. Given that my machine can see the access 
>>> point, but I am either failing authentication or failing to get a 
>>> DHCP lease, what if anything can I do to get more details about what 
>>> exactly is happening?
>
>> You could try iwconfig ra0  or iwlist ra0 scan  to see if an ESSID is 
>> reported.
>
> 'kay, let's see if I understand this. ESSID is, informally speaking, 
> the name of the network, isn't it? If so, yes, it usually shows up in 
> the list displayed by the wicd GUI, and I also see it when I run

It means Extended Service Set ID.  In common parlance, it is the name of 
your wireless connection, or AP (Access Point).  Clumsy terms and 
acryonyms seem to be a requirement. :) 
>   iwlist scanning
>
> which is basically the same as your command, isn't it? Also, I don't 
> have ra* interfaces, I have wlan*. But that's just a different naming 
> convention, right?

Hmm.  I've never run iwlist without providing the interface.  I'll 
remember this.

Yes and no.  Ralink chips usually use ra*.  Atheros uses ath*.  Some 
other chips use wlan*.
> A couple of things that I maybe should have pointed out earlier:
>
>  * Sometimes when I can't connect, nobody else can. But I am aware of
>    several occasions when I couldn't connect, but Windows and Mac users
>    in the place could. Most of the time the coffee shop staff *think*
>    their network is running fine, which may or may not be true.
>
>  * According to the status messages from the wicd GUI, authentication
>    seems to take a really long time (30 seconds?). In most cases, though
>    there is no message saying that authentication succeeded, it goes on
>    to say that it is obtaining an IP address--but that always fails. I
>    think the message is "Failed to obtain IP address."
>

It sounds like the DHCP server or the wireless router might have quit 
running or has some other problem.  If the DHCP server stops serving 
addresses, people already connected won't have a problem until their 
lease expires.

Some inexpensive wireless routers aren't very good.  Some lock up after 
they have run for a while and cycling power helps.  Some reset 
automatically after so much time; maybe tables get full or something.  
When they reset, they sometimes forget all of their settings.  Again, 
cycling power seems to work.  Some routers can be flashed with Tomato, 
OpenWRT, etc., which often helps.

> You know, it occurs to me that part of the difficult I have with WiFi 
> comes from not knowing the jargon, because I have RTFM'ed on this 
> issue, but I don't understand, for example, most of the iwconfig man 
> page. Can you recommend a good glossary of wireless networking 
> terminology?
>

I don't know where to find a good glossary.  There doesn't seem to be a 
comprehensive source.  Maybe someone else in the group knows of one.