[vox-tech] Wireless Networking

[Peter Salzman]

On Wed, Jul 28, 2010 at 2:14 PM, Chanoch (Ken) Bloom <kbloom at gmail.com>wrote:

> On Wed, Jul 28, 2010 at 12:42:36PM -0400, Peter Salzman wrote:
> > I'm having a horrendously awful time getting wireless networking working
> on
> > my Kubuntu box.   I've never played around with wireless networking on
> Linux
> > before and wanted to consolidate my knowledge and see if I understand it
> > correctly.   My two wireless cards are:
> >
> > Edimax EW-7318usg
> >      148F:2573 Ralink Technology, Corp. RT2501USB wireless adapter
> >
> > Alfa AWUS050NH
> >      148F:2770 Ralink Technology, Corp.
> >
> > If this were wired networking, the steps I would take would be:
> >
> > 1. Plug in the card into the computer and connect it to the router.
> > 2. Load the correct driver.
> > 3. Bring the interface up and assign an IP addr, either manually with
> > ifconfig or automatically with dhclient.
> > 3a. If manual was used in step 3, resolv.conf must contain the DNS
> servers
> > and a gateway must be specified with "route".
> >
> > I assume wireless networking must work more or less the same way.   The
> two
> > things that are causing me grief are:
> >
> > 1. I don't know if the drivers are correct.
>
> dmesg should clue you in to that.
> You can also run ifconfig -a or iwconfig to see whether the interface
> appears in the list. If that works, then your driver works. (Well, if
> it appears in the list but doesn't work, then you're into bug hunting,
> really.)
>

Unfortunately, that's kind of where I am, and part of why it's so
frustrating.  The interfaces definitely show up, but I can't connect to the
WAN.

I wasn't sure if it was non-functional driver, wpa_supplicant not working,
some option or parameter that needs to be set somewhere.

So you're saying that if the interface can be brought up, say, by "ifconfig
wlan1 192.168.0.5 up" then I can safely cross driver off the list of
possible things that went wrong?


> > 2. Security details (WEP, WPA, etc)
>
> Use wpasupplicant.
>
> wpasupplicant maintains a configuration file with a list of networks
> and their encryption types and passwords. When you run wpasupplicant,
> it looks to see what's available that it knows about, picks one and
> connects (to the wireless router -- then it's your job to set up the
> IP address yourself.) If it doesn't know about any of the available
> networks, it doesn't connect to any of them, even if they're
> unencrypted.
>
> For some security confiurations (pretty much only WEP), you can use
> iwconfig.  iwconfig is the low level tool for connecting
> to the network.  It doesn't remember anything about any networks (kinda
> like how ifconfig works)
>

OK, I had no idea, but this is great info!  If worse comes to worse, I'll
set network security to WEP temporarily.


> Either way, you can check whether it worked by running iwconfig -- it
> it says "Access Point: Not-Associated", you failed. If it gives a MAC
> address, then you succeded.
>
> Your new set of steps:
>
> 1. Plug in the card into the computer and connect it to the router.
>   (check by looking at dmesg to see the USB subsystem recognizes that
>  it was plugged in.)
> 2. Load the correct driver. (May happen automatically by udev)
>  (check by running ifconfig -a to see what name the interface was
>  given)
> 3. Bring the interface up and connect to a wireless network
>  option 1: use wpa_supplicant for all of this.
>  option 2: use ifconfig/iwconfig for the various steps
>  (check by running iwconfig to see whether it's associated with a
>  particular MAC address. Maybe you could do some kind of arp lookup
>  at this point also.)
> 4. Assign an IP address
>  option 1: dhclient
>  option 2: ifconfig/route/vi resolv.conf
>  (check by pinging something)
>
> In general, you probably want to use something like network-manager or
> wicd to handle connecting to wireless networks. Even if you'd
> ordinarily prefer to write your own networking configuration script,
> or hard code information in  /etc/network/interfaces, and let Debian
> do it for you you're most likely going to be using a lot more
> different networks (with a lot more varied configurations) with your
> wireless card than you typically do with your wired ethernet.
>
> If you've reached the driver step and successfully loaded the driver,
> you can watch the state of your wireless card in real time using wavemon
> It will show you signal strength, which AP you're associated with, and
> your IP address as they change (which can be useful to have in another
> window while you're fighting through the details of configuring the
> network.) <http://lists.lugod.org/mailman/listinfo/vox-tech>


Awesome!!!    The wavemon idea is spectacular.   Hope to report good news
tonight.

Pete
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