Hi,

I have had the wireless connection from my router to my laptop working successfully for months, and then all of a sudden today I can't connect. The router is set up correctly, and has security off (for now). I don't seem to be able to communicate at all with the router (ping'ing results in 'connect: Network is unreachable'). Following are some things I tried. I'd be grateful for any suggestions on how to troubleshoot this problem.

Thanks
-Paul

$ sudo /sbin/iwconfig wlan0 essid ACK key OFF
$ iwconfig
lo no wireless extensions.

eth0 no wireless extensions.

wmaster0 no wireless extensions.

wlan0 IEEE 802.11abg ESSID:"ACK"
Mode:Managed Frequency:2.412 GHz Access Point: Not-Associated
Tx-Power=0 dBm
Retry min limit:7 RTS thrff Fragment thr=2352 B
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

$ sudo /sbin/ifconfig wlan0 up
SIOCSIFFLAGS: No such device
SIOCSIFFLAGS: No such device
wmaster0: unknown hardware address type 801
Listening on LPF/wlan0/00:1f:3c:cf:00:3d
Sending on LPF/wlan0/00:1f:3c:cf:00:3d
Sending on Socket/fallback
receive_packet failed on wlan0: Network is down
DHCPDISCOVER on wlan0 to 255.255.255.255 port 67 interval 7
send_packet: Network is down

$ lspci | grep ireless
0b:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG Network Connection (rev 02)

$lshw -C network
*-network
description: Ethernet interface
product: 88E8040 PCI-E Fast Ethernet Controller
vendor: Marvell Technology Group Ltd.
physical id: 0
bus info: pci@0000:09:00.0
logical name: eth0
version: 12
serial: 00:23:ae:11:58:fd
width: 64 bits
clock: 33MHz
capabilities: bus_master cap_list ethernet physical
configuration: broadcast=yes driver=sky2 driverversion=1.20 firmware=N/A latency=0 module=sky2 multicast=yes
*-network DISABLED
description: Wireless interface
product: PRO/Wireless 3945ABG Network Connection
vendor: Intel Corporation
physical id: 0
bus info: pci@0000:0b:00.0
logical name: wmaster0
version: 02
serial: 00:1f:3c:cf:00:3d
width: 32 bits
clock: 33MHz
capabilities: cap_list logical ethernet physical wireless
configuration: broadcast=yes driver=iwl3945 latency=0 module=iwl3945 multicast=yes wireless=IEEE 802.11abg

This appear to be a hardware problem - may be ubuntu could not load the drivers for your wireless card.

Can you type on root console:
modprobe -r iwl3945
modprobe iwl3945
dmesg | tail -n 30

Post outputs please.

Thank you for the response. Here's what I got:

root@jaguar:~# modprobe -r iwl3945
root@jaguar:~# modprobe iwl3945
root@jaguar:~# dmesg | tail -n 30
[ 40.197363] iwl3945: Radio disabled by HW RF Kill switch
[ 40.197467] ACPI: PCI interrupt for device 0000:0b:00.0 disabled
[ 45.392640] CPU0 attaching NULL sched-domain.
[ 45.392651] CPU1 attaching NULL sched-domain.
[ 45.400031] CPU0 attaching sched-domain:
[ 45.400042] domain 0: span 03
[ 45.400046] groups: 01 02
[ 45.400053] domain 1: span 03
[ 45.400056] groups: 03
[ 45.400061] CPU1 attaching sched-domain:
[ 45.400064] domain 0: span 03
[ 45.400067] groups: 02 01
[ 45.400074] domain 1: span 03
[ 45.400077] groups: 03
[ 56.720190] iwl3945: Intel(R) PRO/Wireless 3945ABG/BG Network Connection driver for Linux, 1.2.26k
[ 56.720201] iwl3945: Copyright(c) 2003-2008 Intel Corporation
[ 56.720376] ACPI: PCI Interrupt 0000:0b:00.0[A] -> GSI 17 (level, low) -> IRQ 17
[ 56.720404] PCI: Setting latency timer of device 0000:0b:00.0 to 64
[ 56.720432] iwl3945: Detected Intel Wireless WiFi Link 3945ABG
[ 56.762336] iwl3945: Tunable channels: 11 802.11bg, 13 802.11a channels
[ 56.763617] phy0: Selected rate control algorithm 'iwl-3945-rs'
[ 56.765206] input: 3945ABG as /devices/pci0000:00/0000:00:1c.1/0000:0b:00.0/input/input10
[ 56.822020] ACPI: PCI Interrupt 0000:0b:00.0[A] -> GSI 17 (level, low) -> IRQ 17
[ 56.831202] iwl3945: Radio disabled by HW RF Kill switch
[ 56.833130] ACPI: PCI Interrupt 0000:0b:00.0[A] -> GSI 17 (level, low) -> IRQ 17
[ 56.833699] iwl3945: Radio disabled by HW RF Kill switch
[ 56.855041] ACPI: PCI Interrupt 0000:0b:00.0[A] -> GSI 17 (level, low) -> IRQ 17
[ 56.855454] iwl3945: Radio disabled by HW RF Kill switch
[ 56.855626] ACPI: PCI Interrupt 0000:0b:00.0[A] -> GSI 17 (level, low) -> IRQ 17
[ 56.856032] iwl3945: Radio disabled by HW RF Kill switch

And answer is:
iwl3945: Radio disabled by HW RF Kill switch

It is turned off by hardware "button"=switch.

Search for it in google, has to be a lot of information.

The answer is, I'm an idiot. The wireless switch on the side of the laptop had somehow gotten turned off; turning it back on of course solved the problem. Thanks to the respondents for their help, which led me to consider the possibility that there was a physical switch on the laptop, and sorry for wasting your time.

-Paul

iwl3945: Could not read microcode: -2
iwl3945: iwlwifi-3945-2.ucode firmware file req failed: -2
iwl3945: iwlwifi-3945-1.ucode firmware file req failed: -2
iwl3945: Could not read microcode: -2
ACPI: PCI interrupt for device 0000:02:00.0 disabled
cfg80211: Calling CRDA to update world regulatory domain
cfg80211: World regulatory domain updated:
(start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
(2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
(2457000 KHz - 2482000 KHz @ 20000 KHz), (300 mBi, 2000 mBm)
(2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm)
(5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
(5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
iwl3945: Intel(R) PRO/Wireless 3945ABG/BG Network Connection driver for Linux, 1.2.26ks
iwl3945: Copyright(c) 2003-2009 Intel Corporation
PCI: Enabling device 0000:02:00.0 (0000 -> 0002)
ACPI: PCI Interrupt 0000:02:00.0[A] -> GSI 16 (level, low) -> IRQ 16
PCI: Setting latency timer of device 0000:02:00.0 to 64
iwlagn: Tunable channels: 11 802.11bg, 13 802.11a channels
iwl3945: Detected Intel Wireless WiFi Link 3945ABG
phy0: Selected rate control algorithm 'iwl-3945-rs'
iwl3945: iwlwifi-3945-2.ucode firmware file req failed: -2
iwl3945: iwlwifi-3945-1.ucode firmware file req failed: -2
iwl3945: Could not read microcode: -2
iwl3945: iwlwifi-3945-2.ucode firmware file req failed: -2
iwl3945: iwlwifi-3945-1.ucode firmware file req failed: -2
iwl3945: Could not read microcode: -2
iwl3945: iwlwifi-3945-2.ucode firmware file req failed: -2
iwl3945: iwlwifi-3945-1.ucode firmware file req failed: -2
iwl3945: Could not read microcode: -2
[root@localhost rc.d]#