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I am using Ubuntu 10.04 (LTS) on a Samsung N150+ netbook. I cannot scan wifi networks using iwlist and I would like to do so. Here is the output from some tests:

alex@alex-laptop:~/Desktop/GoogleCode$ iwlist eth1 scan
eth1      Interface doesn't support scanning.

alex@alex-laptop:~/Desktop/GoogleCode$ iwlist scan
lo        Interface doesn't support scanning.

eth0      Interface doesn't support scanning.

eth1      Interface doesn't support scanning.

pan0      Interface doesn't support scanning.

So I try iwconfig

alex@alex-laptop:~/Desktop/GoogleCode$ iwconfig
lo        no wireless extensions.

eth0      no wireless extensions.

eth1      IEEE 802.11  Access Point: Not-Associated   
      Link Quality:5  Signal level:207  Noise level:168
      Rx invalid nwid:0  invalid crypt:0  invalid misc:0

pan0      no wireless extensions.

I have a 05:00.0 Network controller: Broadcom Corporation Device 4727 (rev 01) from using lspci.

Any hints?

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Did you try scanning as root? – jordanm Aug 12 '12 at 23:06
@jordanm, this is a bit embarrassing but you are right that root was a necessary condition which I did not try. Could you put this as an answer? – Vass Aug 14 '12 at 6:42
glad it helped. answer added. – jordanm Aug 14 '12 at 16:31

You have to bring eth1 up before scanning.

ifconfig eth1 up

iwlist eth1 s

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Being root or this didn't help me neither. But NetworkManager doesn't have any issue to scan the networks. Any idea ? – vaab Jan 15 '15 at 4:57

The ability to scan using iwlist and associate to access points via iwconfig require root. In Ubuntu you can use the following:

sudo iwlist eth1 scan
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Thanks. For me that does not resolve the issue. Would you have any other suggestion? – Alexandre Bourlier Aug 3 '14 at 15:23
for people as confused as i am, this may happen: on my arch system, sudo iw eth1 scan fails but sudo iwlist eth1 scan succeeds – Francois Mar 30 at 15:00

If you have checked that you are root and your device is up:

sudo ifconfig eth1 up && sudo iwlist eth1 scan

And it still doesn't work, I found that:

iw dev wlan0 scan ap-force

Would work in my case. It seems that iwlist tool is obsolete and not anymore supported for recent wifi chipset.

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