Arch Linux

monkd

Member

From: Finland

Registered: 2007-02-11

Posts: 11

Weird wifi problem -- scan doesn't find own wireless network

Hi,

This morning when I got to my computer my wifi was down. I tried to reconnect to it but it didn't work. When I scan for wireless networks with

iwlist wlan0 scan

it finds my neighbors' wifis but not my own. I can connect to my wifi with my phone and with my own and my gf's laptop
(one of them has arch on it, so I know it should work) but my stationary can't find the wifi. I have win7 on the same box, when I booted win7 up it found my wifi and connected to it.

I have tried to reset the router to factory defaults -- didn't help
I have tried to connect to my wifi with netcfg and with the manual way

# ip link set wlan0 up
# iwlist wlan0 scan
# iwconfig essid "my_wifi" # (here I just typed in the ESSID even though the scan didn't return it)
# dhcpcd wlan0

I heard some strange noices last night, maybe it's a troll fucking with my computer, now when we're nearing xmas and all...

I don't have a net cable that's long enough to reach to my computer (and it looks a lot neater without it) so I have to use wifi.
Any help on this would be much appreciated!

Cheers,
monkd

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 19,804

Re: Weird wifi problem -- scan doesn't find own wireless network

Hi,

This morning when I got to my computer my wifi was down. I tried to reconnect to it but it didn't work. When I scan for wireless networks with

iwlist wlan0 scan

it finds my neighbors' wifis but not my own. I can connect to my wifi with my phone and with my own and my gf's laptop
(one of them has arch on it, so I know it should work) but my stationary can't find the wifi. I have win7 on the same box, when I booted win7 up it found my wifi and connected to it.

# ip link set wlan0 up
# iwlist wlan0 scan
# iwconfig essid "my_wifi" # (here I just typed in the ESSID even though the scan didn't return it)
# dhcpcd wlan0

Those commands lead me to believe you are using an open router -- No WPA, no WEP.  If that is not the case, the above won't work.
Have you upgraded your system lately? Did you restart afterword (in case something in the kernel or WIFI stack changed)?

What is the output of rfkill list  ??
What is your WIFI chipset (If you can, post the output of lspci -nn   (That is two n's, not m)

Edit:  Also, you might try to reboot your router.

Last edited by ewaller (2011-11-18 16:46:21)

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Leonid.I

Member

From: Aethyr

Registered: 2009-03-22

Posts: 999

Re: Weird wifi problem -- scan doesn't find own wireless network

iwlist is really crappy on some cads, I had similar issues on an old broadcom chip. Try using iw (in fact, you don't need wireless_tools any more).

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Arch Linux is more than just GNU/Linux -- it's an adventure
pkill -9 systemd

monkd

Member

From: Finland

Registered: 2007-02-11

Posts: 11

Re: Weird wifi problem -- scan doesn't find own wireless network

Yeah, I'm using an open router. I don't have rfkill installed. But the wifi has worked for 3 months. I did an upgrade about a week ago but didn't reboot after that.

My WIFI chipset:

$ lspci -nn
...
02:00.0 Ethernet controller [0200]: Atheros Communications AR8121/AR8114 Gigabit or Fast Ethernet [1969:1026] (rev b0)
04:00.0 Ethernet controller [0200]: Atheros Communications Inc. AR5007G Wireless Network Adapter [168c:001d] (rev 01)
...

When I try bringing my network profile up with netcfg it fails with

> WPA Authentication/Association Failed                                [FAIL]

I don't have any encryption on my router. Like I said our other computers are connected to the wifi *without* encryption. And I have restarted my router several times and also reset it to factory defaults. I have shutdown my computer and restarted it. Still only shows my neighbors' networks when scanning. I have upgraded my laptop which has arch on it and with it I can connect to my wifi. Strange.

Cheesecake Charlie

Member

Registered: 2011-09-08

Posts: 94

Re: Weird wifi problem -- scan doesn't find own wireless network

iwlist is really crappy on some cads, I had similar issues on an old broadcom chip. Try using iw (in fact, you don't need wireless_tools any more).

Why dont you need wireless_tools anymore ?

Gusar

Member

Registered: 2009-08-25

Posts: 3,605

Re: Weird wifi problem -- scan doesn't find own wireless network

Why dont you need wireless_tools anymore ?

Because they use the deprecated wext (wireless extensions) in a time where all drivers use netlink. The only reason wireless_tools still works at all is because netlink has a wext compatibility layer. But that layer will be marked for removal soon.

Cheesecake Charlie

Member

Registered: 2011-09-08

Posts: 94

Re: Weird wifi problem -- scan doesn't find own wireless network

Why dont you need wireless_tools anymore ?

Because they use the deprecated wext (wireless extensions) in a time where all drivers use netlink. The only reason wireless_tools still works at all is because netlink has a wext compatibility layer. But that layer will be marked for removal soon.

Oh ok and this is just for use with netcfg then ?

Gusar

Member

Registered: 2009-08-25

Posts: 3,605

Re: Weird wifi problem -- scan doesn't find own wireless network

This has nothing to do with netcfg. Netcfg uses wpa_supplicant and iproute2.

monkd

Member

From: Finland

Registered: 2007-02-11

Posts: 11

Re: Weird wifi problem -- scan doesn't find own wireless network

I couldn't get it to work. I had to change my ssid for iw to discover my (renamed) wifi network. Still have no idea what caused this but changing the ssid solved this. Thanks for replies