WiFi with iwconfig

Hi,

I want to connect to an wireless access point using iwconfig. The
connection seems to work but ifconfig then indicates that no IP
was assigned to the wireless card (wlan0).

These are the steps I did:

"iwlist wlan0 scan":
wlan0 Scan completed :
Cell 01 - Address: 00:23:04:XXX
ESSID:"BLA"
Mode:Master
Channel:1
Frequency:2.412 GHz (Channel 1)
Quality=73/100 Signal level=-61 dBm Noise level=-88
dBm
Encryption keyff
Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s
11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s
48 Mb/s; 54 Mb/s
Extra:tsf=00000413bf3c5e3

"iwconfig wlan0 essid BLA"

"iwconfig":
wlan0 IEEE 802.11g ESSID:"BLA"
Mode:Managed Frequency:2.412 GHz Access Point: 00:23:04:XXX
Bit Rate=54 Mb/s Tx-Power=27 dBm
Retry min limit:7 RTS thrff Fragment thr=2352 B
Encryption keyff
Link Quality=51/100 Signal level=-78 dBm Noise level=-88 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0


"ifconfig wlan0":
wlan0 Link encap:Ethernet HWaddr 00:1B:77:XXX
inet6 addr: fe80::21b:77ff:fe04:32bb/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:416 (416.0 b)

So, it can be seen that wlan0 is connected to the non-encrypted access
point "BLA" but it was not assigned any IP address. On the other hand,
when I connect via kinternet with this access point, wlan0 is also
assigned an IP address, thus the DHCP server of BLA seems to be OK.
It seems that using kinternet the wlan0 connection to BLA is carried
out in a different way.

Any ideas what I'm missing with iwconfig?

Regards,
Tim

> ifconfig $wireless_interface $wireless_ip netmask $netmask up
> ifconfig $wireless_interface mtu 576
> route add default gw $gateway_ip

How do I know $wireless_ip, $netmask and $gateway_ip? Are there any
tools that provide this information for the considered access
point?

> Or just use something like dhclient3 or dhcpcd if the access point is
> DHCP based. Granted that for some access points, I still need to
> manually setup a few matching elements before it "works".

Which elements are these in particular?

Tim

Tim Frik <(E-Mail Removed)> wrote:
> Hi,
>
> I want to connect to an wireless access point using iwconfig. The
> connection seems to work but ifconfig then indicates that no IP
> was assigned to the wireless card (wlan0).
>
> These are the steps I did:
>
> "iwlist wlan0 scan":
> wlan0 Scan completed :
> Cell 01 - Address: 00:23:04:XXX
> ESSID:"BLA"
> Mode:Master
> Channel:1
> Frequency:2.412 GHz (Channel 1)
> Quality=73/100 Signal level=-61 dBm Noise level=-88
> dBm
> Encryption keyff
> Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s
> 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s
> 48 Mb/s; 54 Mb/s
> Extra:tsf=00000413bf3c5e3
>
> "iwconfig wlan0 essid BLA"
>
> "iwconfig":
> wlan0 IEEE 802.11g ESSID:"BLA"
> Mode:Managed Frequency:2.412 GHz Access Point: 00:23:04:XXX
> Bit Rate=54 Mb/s Tx-Power=27 dBm
> Retry min limit:7 RTS thrff Fragment thr=2352 B
> Encryption keyff
> Link Quality=51/100 Signal level=-78 dBm Noise level=-88 dBm
> Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
> Tx excessive retries:0 Invalid misc:0 Missed beacon:0
>
>
> "ifconfig wlan0":
> wlan0 Link encap:Ethernet HWaddr 00:1B:77:XXX
> inet6 addr: fe80::21b:77ff:fe04:32bb/64 Scope:Link
> UP BROADCAST MULTICAST MTU:1500 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:0 (0.0 b) TX bytes:416 (416.0 b)
>
> So, it can be seen that wlan0 is connected to the non-encrypted access
> point "BLA" but it was not assigned any IP address. On the other hand,
> when I connect via kinternet with this access point, wlan0 is also
> assigned an IP address, thus the DHCP server of BLA seems to be OK.
> It seems that using kinternet the wlan0 connection to BLA is carried
> out in a different way.
>
> Any ideas what I'm missing with iwconfig?
>
> Regards,
> Tim

DOes the AP use DHCP? If so, have you started a DHCP client?
iwconfig gets you associated at the hardware level, you now need to
configure the TCP/IP networking.

Jerry

On Fri, 31 Jul 2009 08:30:36 +0000, Tim Frik wrote:

> Hi,
>
> I want to connect to an wireless access point using iwconfig. The
> connection seems to work but ifconfig then indicates that no IP was
> assigned to the wireless card (wlan0).
>
> These are the steps I did:
>
> "iwlist wlan0 scan":
> wlan0 Scan completed :
> Cell 01 - Address: 00:23:04:XXX
> ESSID:"BLA"
> Mode:Master
> Channel:1
> Frequency:2.412 GHz (Channel 1)
> Quality=73/100 Signal level=-61 dBm Noise
> level=-88
> dBm
> Encryption keyff
> Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s
> 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36
> Mb/s 48 Mb/s; 54 Mb/s
> Extra:tsf=00000413bf3c5e3
>
> "iwconfig wlan0 essid BLA"
>
> "iwconfig":
> wlan0 IEEE 802.11g ESSID:"BLA"
> Mode:Managed Frequency:2.412 GHz Access Point: 00:23:04:XXX
> Bit Rate=54 Mb/s Tx-Power=27 dBm
> Retry min limit:7 RTS thrff Fragment thr=2352 B
> Encryption keyff
> Link Quality=51/100 Signal level=-78 dBm Noise level=-88 dBm
> Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx
> excessive retries:0 Invalid misc:0 Missed beacon:0
>
>
> "ifconfig wlan0":
> wlan0 Link encap:Ethernet HWaddr 00:1B:77:XXX
> inet6 addr: fe80::21b:77ff:fe04:32bb/64 Scope:Link UP
> BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0
> dropped:0 overruns:0 frame:0 TX packets:4 errors:0 dropped:0
> overruns:0 carrier:0 collisions:0 txqueuelen:1000
> RX bytes:0 (0.0 b) TX bytes:416 (416.0 b)
>
> So, it can be seen that wlan0 is connected to the non-encrypted access
> point "BLA" but it was not assigned any IP address. On the other hand,
> when I connect via kinternet with this access point, wlan0 is also
> assigned an IP address, thus the DHCP server of BLA seems to be OK. It
> seems that using kinternet the wlan0 connection to BLA is carried out in
> a different way.
>
> Any ideas what I'm missing with iwconfig?

dhclient wlan0

to get an IP address from the router's dhcp server.

Also, what does just ifconfig (without wlan0) report? With my wireless I
get both ath0 and wlan0. ath0 is the card. wlan0 does nothing. You may
get eth0 or eth1 for your wireless. Depends on the wireless card chipset
and driver used. My card uses the Atheros chipset with the MadWifi
driver.

Stef