[PLUG] Scanning for and connecting to wifi networks

[John Jason Jordan]

On Sat, 8 Nov 2014 07:12:37 -0800
Michael Rasmussen <michael at jamhome.us> dijo:

>On Fri, Nov 07, 2014 at 11:29:42PM -0800, John Jason Jordan wrote:
>> Xubuntu 14.04.1, fresh install shortly after it was released.
>> I know there are commands that can be used to scan for available wifi
>> networks and to connect to them, but I can't remember what they are
>> and my google fu is failing me. Can someone remind me?

>    iwlist <interface_name> scan
>you can get <interface_name> from
>    iwconfig

Thanks. 

There is a problem in Xubuntu 14.04 that causes the network icon
to fail to appear in the panel. The fix is to have the user edit the
'Exec' line in etc/xdg/autostart to 'dbus-launch nm-applet.' I applied
that fix over a month ago and have had the network icon in the panel
ever since. Clicking on it displays available access points. Normally I
see my own wireless router (which I use only for my phone, as the
computers are all wired), and I see up to half a dozen neighbors.
However, I have never trusted it.

Yesterday my new Toshiba Flashair arrived and I promptly inserted it
into my CPAP machine. The machine is pretty fussy in that it writes
certain files to a new SD card, else it will not use the card. When you
insert a new card it offers to "erase" the card which, from past
experience, means that it will format it to FAT32 and add the necessary
files. It did so and last night it recorded data to the card.

This morning I left the card in the machine and went downstairs to my
laptop, expecting that the card would appear as a wifi network that I
could connect to. However it did not appear. The machine is about 8 or
9 meters plus one floor from the laptop and the advertised range of the
Flashair is supposedly 30 feet. Fearing that it was a distance problem
I went upstairs and removed the card from the machine and took it
downstairs where I inserted it into the laptop SD card port. Xubuntu
promptly auto-mounted it and my software was able to read last night's
data. But when I clicked on the network icon in the panel its wifi was
not visible in the list of available access points. (But see below.)

Then I put my old T61 (Xubuntu 12.04) next to the new laptop, booted it
and inserted the Flashair into a USB card reader, as the card reader
built into the T61 has been broken for years. The T61 promptly
auto-mounted it, and I could see the data. Switching back to the new
laptop I could now see the Flashair in the available access points,
however when I tried to connect to it I got a permissions error. I
tried to read the manual that came with the Flashair expecting to find
that it ships with some default password, but the manual is literally 7
x 10 cm. and the font is about three points. I can barely read it even
with a magnifying glass. Even if I knew the password I may still have a
problem because the nm-applet GUI doesn't pop up a window to enter it.

Then I tried 'iwlist wlan0 scanning' and nothing appeared. I repeated
it and my own wifi network and one of the neighbors showed up. I kept
repeating the command and each time I got a different list of networks,
but none ever included the Flashair. At least half the time my own
wireless network did not appear, even though the WRT54G sits barely a
couple of meter from the computer. 

You are also supposed to be able to connect to the Flashair with a
smartphone, but it never appears as an available network on my Note 3
Android phone.

Finally I shut down the T61, removed the Flashair from the USB card
reader, and put it back into the new laptop. The new laptop
auto-mounted it and this time it also appeared in the list of available
networks. I selected it and the nm-applet connected to it, but when I
hover over the spinning network icon with the mouse it says 'User
authentication required for WiFi Network 'flashair_b86b230a97a8.' After
a few moments it disconnects. And it never appears in 'iwlist wlan0
scanning.' 

At this point I am confused and out of ideas. Suggestions and
observations are welcome.