Re: Can Anyone Explain the over-all view of Wireless Networking?
Jochen Schulz wrote:
> Kent West:
>
>> Now I get no dhcp offers received. I don't understand how ifup/down and
>> /etc/modules and udev and /etc/network/interfaces and "wpa-conf
>> /etc/wpa_supplicant/wpa_supplicant.conf" and iwlist/spy/scan/whatever
>> and eth0 vs wlan0 vs sit0 and auto eth1 vs allow-hotplug eth1 and wep vs
>> wep-key vs open vs wpa, etc, all work together.
>>
>
> /etc/modules contains module names that should always be loaded. You
> shouldn't need that for your wireless card, the kernel generally loads
> kernel modules for hardware it can find automatically.
>
Except sometimes you manually have to add modules and sometimes you
don't. However, that seems to be less of an issue in recent years, so
I'm not really worried about that right now.
> Udev is responsible for naming the device and, I think, calling
> userspace programs like ifplugd when a new device is inserted. Unless
> you don't like the device naming, you can probably ignore it.
>
I'm beginning to get a handle on udev renaming eth0 to eth1, so I'm not
terribly worried about this right now either.
> /etc/network/interfaces contains the configuration of all your network
> devices.
Well, that's what I thought, except a couple of people on this thread
told me to remove my wireless from this file and use wicd or
NetworkManager, so it's not always true; and there's this warning when I
run /etc/init.d/networking restart:
> Running /etc/init.d/networking restart is deprecated because it may
> not enable again some interfaces ... (warning).
That's the sort of thing that confuses me.
> Wpa-supplicant is a special tool for configuring wireless encryption
> settings. Additionally, it can use virtual device names from the
> `interfaces` file so that a specific network card can use different
> configurations depending on the available networks. As I understand it,
> your computer is stationary and doesn't use wireless encryption, so you
> can ignore wpa-supplicant as well.
>
Now that starts getting confusing.
> In your case you just need to:
>
> - Make sure the right module (and possibly a related firmware blob) gets
> loaded for your hardware. That already appears to work correctly.
>
> - Determine the device name udev assigns. That appears to be wlan0 in
> your case.
>
> - Find out the SSID you want to connect to. That's probably "ACUwireless".
>
> - Find out whether this network uses encryption. ACUwireless doesn't.
>
> - Find out whether you have to configure a static address, gateway and
> DNS server or whether you just need to enable DHCP.
>
> For DHCP and no encryption put the following in the `interfaces` file:
>
> auto wlan0
> iface wlan0 inet dhcp
> wireless-essid ACUWireless
>
>
> That should be it. Just run '/etc/init.d/networking restart' and
> everything should be fine. You just might want to kill all dhclient
> instances before doing that.
>
> If it doesn't, first check whether your card is actually associated to
> an AP. Just run 'iwconfig wlan0' and look for the second line:
>
> wlan0 IEEE 802.11abgn ESSID:"landfill"
> Mode:Managed Frequency:2.412 GHz Access Point: 00:90:4C:5F:00:2A
>
> After "Access Point" there should be a hexa-decimal string just like in
> my example. If this looks fine but DHCP still doesn't work, I am
> temporarily out of ideas. :)
>
Ah, a clue!
westk@evoljasen:~$ sudo iwconfig wlan0
wlan0 IEEE 802.11bg ESSID:"ACUWireless"
Mode:Managed Frequency:2.412 GHz Access Point: Not-Associated
Tx-Power=27 dBm
Retry min limit:7 RTS thr:off Fragment thr:off
Encryption key:off
Power Management:off
Link Quality:0 Signal level:0 Noise level:0
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
So, how do I associate an Access Point?
--
Kent West <*)))><
http://kentwest.blogspot.com
Praise Yah! \o/
Reply to: