anyone knows how to scan wireless signal?


Forum: User Feedback
Topic: anyone knows how to scan wireless signal?
started by: toufu

Posted by toufu on Jan. 01 2008,19:32
I try: "iwlist wlan0 scanning"
Not working. Error message:
"wlan0 Failed to read scan data: Function not implemented"

DSL version 4.2.1.
Wireless adapter: Syntax USB-400


Thanks.

Posted by roberts on Jan. 01 2008,23:32
That same command works on my Atheros AirLink wireless card.
Posted by bpalone on Jan. 02 2008,03:35
It just worked with my OLD Belkin 54g as well.

I would guess that it has to do with your adapter being USB.  I am new to DSL and am still learning.  But, that is my first thought.

Posted by curaga on Jan. 02 2008,10:38
It's not the usb that matters.. Either your wlan adapter doesn't support scanning, or the driver doesn't..
Posted by lucky13 on Jan. 04 2008,22:34
Quote
I try: "iwlist wlan0 scanning"

Scanning or scan? That's a prism device, it should work.

Posted by toufu on Jan. 07 2008,06:10
the USB adapter works fine at windows 2000. It can scan nearby wireless access points. But scanning dones't work in DSL.
Posted by ^thehatsrule^ on Jan. 07 2008,15:34
Quote
Function not implemented
would probably imply the driver doesn't support it.  You could try seeing if there's updated drivers, (or even use ndiswrapper - if this is absolutely required)?

Posted by Juanito on Jan. 08 2008,14:33
Quote
You could try seeing if there's updated drivers, (or even use ndiswrapper - if this is absolutely required)?

- I'm not so sure you can do this with ndiswrapper. I've always had the problem that I need to know the ssid or ssid and wep code before I load ndiswrapper or otherwise it will not load.

If ndiswrapper has not loaded/connected then things will not work:
Code Sample
$ sudo /usr/local/bin/ndiswrapper.sh /mnt/sda1/ndiswrapper/bcmwl5a.inf wlan0 ssid 2>&1 >/dev/null
Operation failed
$ iwlist wlan0 scanning
wlan0     No scan results [even though a network is present]

Posted by Juanito on Jan. 10 2008,06:55
...but if ndiswrapper does connect then everything seems to work fine:
Code Sample
$ sudo /opt/myndis.sh
$ iwlist wlan0 scanning
Warning: Driver for device wlan0 recommend version 18 of Wireless Extension,
but has been compiled with version 16, therefore some driver features
may not be available...
wlan0     Scan completed :
         Cell 01 - Address: 00:12:17:71:0F:5C
                   ESSID:"juanito"
                   Protocol:IEEE 802.11b
                   Mode:Managed
                   Frequency:2.437GHz
                   Quality:0/100  Signal level:-56 dBm  Noise level:-256 dBm
                   Encryption key:on
                   Bit Rate:1Mb/s
                   Bit Rate:2Mb/s
                   Bit Rate:5.5Mb/s
                   Bit Rate:6Mb/s
                   Bit Rate:9Mb/s
                   Bit Rate:11Mb/s
                   Bit Rate:12Mb/s
                   Bit Rate:18Mb/s
                   Bit Rate:24Mb/s
                   Bit Rate:36Mb/s
                   Bit Rate:48Mb/s
                   Bit Rate:54Mb/s
                   Extra:bcn_int=100
                   Extra:atim=0

- maybe dsl-3.4.8 could be updated to version 18 of the wireless extensions (I think 28 or 29 is current now)?

Posted by lucky13 on Jan. 10 2008,16:30
Quote
maybe dsl-3.4.8 could be updated to version 18...

And maybe DSL-4.2.4? :)

Quote
(I think 28 or 29 is current now)

Current is 29 but no support for 2.4 kernel beyond patches for 17 and 18.
< http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/Tools.html >

Patch quick links:
v17: for kernel 2.4.29. Export driver event capacities, allow large scan requests and various minor fixes.
< http://www.hpl.hp.com/persona....13.diff >

v18: for kernel 2.4.30. WPA support, from Jouni Malinen. You will need WT-27-pre25 or later.
< http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/iw240_we18-5.diff >

Posted by kuky on Jan. 12 2008,16:58
Someone knows if these gadget works in dsl ?


< https://shop.fon.com/FonShop....D-DET01 >
*edited goto wifi detector*
you have a movil wireless scanner and wifi-card

edited another

< http://www.comprawifi.com/herrami....26.html >

Posted by lucky13 on Jan. 12 2008,19:37
Quote
Someone knows if these gadget works in dsl ?

It should work like any other wifi since it's a standard 802.11g router that offers two signals; one is for the primary user and the second is for other Fon subscribers. The user can decide how much bandwidth to allocate for sharing with other Fon users. You don't need a separate wifi card to use it (just what you already have).
< http://lucky13linux.wordpress.com/2007....get-fon >

Posted by doglover on Jan. 13 2008,21:50
Need to be root. With Knoppix, I get a similar message if not root, but with sudo it works. Interestingly, if you are not root then you can try to scan as many times as you want, and it won't work. On the other hand, if you iwlist scanner once as root, it will then work thereafter whether root or not. Interesting behavior.
Posted by Tim-O on Jan. 26 2008,03:48
On my Toshiba 2515CDS laptop running DSL3.4 with a MyEssentials PCMCIA WiFi card containing an Atheros chipset I don't believe ndiswrapper is being used at all. But if I don't execute "ifconfig ath0 up" first (from a root session) then my "iwlist ath0 scan" command is rejected with "ath0 ... Interface doesn't support scanning : Invalid argument" error. Once I execute "ifconfig ath0 up" the scan goes OK!
Posted by jpeters on Jan. 26 2008,04:49
Quote (Tim-O @ Jan. 25 2008,22:48)
On my Toshiba 2515CDS laptop running DSL3.4 with a MyEssentials PCMCIA WiFi card containing an Atheros chipset I don't believe ndiswrapper is being used at all. But if I don't execute "ifconfig ath0 up" first (from a root session) then my "iwlist ath0 scan" command is rejected with "ath0 ... Interface doesn't support scanning : Invalid argument" error. Once I execute "ifconfig ath0 up" the scan goes OK!

I don't run ndiswrapper OR ifconfig ath0 up, and can scan (after loading the card and using iwconfig).  "ifconfig" will show what is or is not already loaded.
Posted by lucky13 on Jan. 26 2008,06:00
Quote
...containing an Atheros chipset I don't believe ndiswrapper is being used at all.

Atheros doesn't require ndiswrapper, which is only used for cards and adapters that lack native Linux drivers and for which the Windows binary drivers must be kludged to work in Linux. The support of features in ndiswrapper is limited by factors such as version of wireless extension, version of wireless tools, and version of ndiswrapper. Some cards and adapters work much better than others.

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