Mysteries of WiFi #1 - which interface?

[Timothy Murphy]

Paul Johnson wrote:

> The first thing that struck me about your note is that you don't have
> much detail on your wireless card--the hardware itself, and your
> version of the kernel.  Since so many cards exist, and the kernel has
> good support for only some, it is an important detail.  You can
> usually see what you have by running "/sbin/lspci"

Thanks for all your suggestions.

The card I am using in this ThinkPad T43 laptop at the moment is
an Orinoco Classic Silver PCMCIA card.
Actually, I have it working at this instant under NetworkManager (NM).
Typically, it didn't start when I re-booted under NM.
Then when I booted again it did.

The main difference seems to be that on the first occasion
I got the message (in /var/log/messages)
-----------------------------------------
Mar  9 19:04:13 mary NetworkManager: <info>  Activation (eth1/wireless):
        association took too long, failing activation.
-----------------------------------------

> So if you don't make some progress, you should start googling for your
> specific network hardware.

I think I'm using the standard driver orinoco_cs for my PCMCIA card.
I thought of compiling the latest version from source
(I've done this for a USB device)
but decided this was unlikely to help.

>  After logging in, I try to make wireless work manually. I start by
> trying system-config-network to see if it spots the right hardware and
> can try to create a setup.

I think I've found system-config-network works about 1 time in 10,
or less, for me.
What I find more annoying is that there is absolutely no hint,
as far as I can see, about what it is trying to do.

> You find out a lot about your situation by running
> 
> /sbin/iwlist scan

My experience is that this only works if the network is already up,
in which case it is probably unnecessary.

> and
> 
> /sbin/ifconfig

Well, I always run ifconfig and iwconfig just to reassure me,
but I don't think I've ever found it helpful.
Actually, iwconfig is fairly useless,
since it just seems to remember the last successful connection.

> I go like this at least 3 times before giving up.
> 
> /sbin/ifup eth1

Again, I often try this, but it seldom helps.

>>  1. /etc/udev/rules.d/70-persistent-net.rules
>>  with lines like
>>  SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*",
>>         ATTR{address}=="00:02:2d:1d:43:b7", ATTR{type}=="1", NAME="eth0"
>>
> 
> These are re-written when you log out/in.  Some people say the
> persistance interferes with efforts to fix systems.  I was having a
> lot of trouble changing drivers, some people said it was because of
> this.  People recommend that, when  you have trouble, you can just
> delete 70-persistent-net.rules and then restart.

Thanks, that sounds like a good idea.
I haven't tried it because it seemed too drastic.

>>  2. /etc/modprobe.conf
>>  with lines like "alias eth0 orinoco_cs"
>>
> 
> There's some information. you have an orinoco wireless?  and you
> system-config-network has tried to attach the name eth0 to it.

Yes,
In my experience system-config-network has no problem
finding my hardware and an appropriate driver.
But this does not seem to help it much.

> That is somewhat unusual, usually it will have eth0 set aside for the
> wire network and either eth1 or wlan0 for wireless.

I should have said eth1.

> I think that, if you really want to get down to basics and find out
> what works, you turn off NetworkManager and network services, and try
> to really understand.

> The true experts on wireless recommend we use iwconfig directly.
> Here's a sample series of commands I copied from another post. I think
> this approach is "as close to the basics" as you can get.
> 
> iwconfig wlan0 ssid SSID-NAME
> iwconfig wlan0 key YOUR-KEY
> iwconfig wlan0 mode RESTRICTED or OPEN
> 
> ifconfig wlan0 up

I do do more or less this, but it rarely works.
With my card and setup, the only thing that works reasonably often
is re-booting.

> If you can make this work, then you know the hardware can be made to
> work, and the problem is just finding out which pimpy pointy clicky
> thing works.

I haven't found anything that is guaranteed to work,
with this particular card + laptop.

They work without problem under Windows.
And my 3 other laptops (one with identical card)
work without any problems at all.

As I said, what annoys me most is that there is apparently no way,
without reading the source, to see exactly where things break down.

-- 
Timothy Murphy  
e-mail (<80k only): tim /at/ birdsnest.maths.tcd.ie
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland