Troubleshooting Wireless

1. Fedora
2. wireless card you would like to get working

1. uname - tells you the version of the kernel you are running, useful to know when trying to get the wireless card working with Fedora

$ uname -a
Linux localhost.localdomain 2.6.25.10-86.fc9.i686 #1 SMP Mon Jul 7 20:46:03 EDT 2008 i686 i686 i386 GNU/Linux

2. dmesg - displays information that can be used to help troubleshoot faults.

$ dmesg
SNIP
ADDRCONF(NETDEV_UP): wlan0: link is not ready
wlan0: Initial auth_alg=0
wlan0: authenticate with AP 00:0e:2e:c7:e5:7f
wlan0: RX authentication from 00:0e:2e:c7:e5:7f (alg=0 transaction=2 status=0)
wlan0: authenticated
wlan0: associate with AP 00:0e:2e:c7:e5:7f
wlan0: RX AssocResp from 00:0e:2e:c7:e5:7f (capab=0x431 status=0 aid=1)
wlan0: associated
wlan0: switched to long barker preamble (BSSID=00:0e:2e:c7:e5:7f)
ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready

3. lspci - displays more detailed information about the hardware of your wireless card, the following command will also tell you which kernel module is being used.

$ /sbin/lspci -v

02:00.0 Network controller: RaLink RT2561/RT61 802.11g PCI
        Subsystem: RaLink EW-7108PCg
        Flags: bus master, slow devsel, latency 64, IRQ 11
        Memory at 34000000 (32-bit, non-prefetchable) [size=32K]
        Capabilities: 
        Kernel driver in use: rt61pci
        Kernel modules: rt61pci

4. modinfo - displays information about the version of the kernel module used to make your wireless card work along with the name of the firmware file, replace rt61pci with the results of the previous lspci -v command for you card

$ modinfo rt61pci
filename:       /lib/modules/2.6.24.3-34.fc8/kernel/drivers/net/wireless/rt2x00/rt61pci.ko
license:        GPL
firmware:       rt2661.bin
firmware:       rt2561s.bin
firmware:       rt2561.bin
description:    Ralink RT61 PCI & PCMCIA Wireless LAN driver.
version:        2.1.4
author:         http://rt2x00.serialmonkey.com
srcversion:     B24486EDEB73036BAEB0438
alias:          pci:v00001814d00000401sv*sd*bc*sc*i*
alias:          pci:v00001814d00000302sv*sd*bc*sc*i*
alias:          pci:v00001814d00000301sv*sd*bc*sc*i*
depends:        rt2x00lib,rt2x00pci,crc-itu-t,eeprom_93cx6
vermagic:       2.6.24.3-34.fc8 SMP mod_unload 686 4KSTACKS

5. ifconfig - gives you detailed information about the network interfaces on your machine.

$ ifconfig -a
lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:3153 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3153 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:2921024 (2.7 MiB)  TX bytes:2921024 (2.7 MiB)

wlan0     Link encap:Ethernet  HWaddr 00:0E:2E:C7:FE:49  
          inet addr:192.168.2.100  Bcast:192.168.2.255  Mask:255.255.255.0
          inet6 addr: fe80::20e:2eff:fec7:fe49/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:56 errors:0 dropped:0 overruns:0 frame:0
          TX packets:91 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:13650 (13.3 KiB)  TX bytes:12859 (12.5 KiB)

wmaster0  Link encap:UNSPEC  HWaddr 00-0E-2E-C7-FE-49-78-07-00-00-00-00-00-00-00-00  
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

6. iwconfig - tells you about your wireless card

$ iwconfig
lo        no wireless extensions.

wmaster0  no wireless extensions.

wlan0     IEEE 802.11g  ESSID:"default"  
          Mode:Managed  Frequency:2.462 GHz  Access Point: 00:0E:2E:C7:E5:7F   
          Bit Rate=54 Mb/s   Tx-Power=27 dBm   
          Retry min limit:7   RTS thr:off   Fragment thr=2352 B   
          Link Quality=72/100  Signal level=-48 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

7. iwlist - Get more detailed wireless information from a wireless interface.
   

$ su -c 'iwlist wlan0 scan'
Password: 
wlan0     Scan completed :
          Cell 01 - Address: 00:0E:2E:C7:E5:7F
                    ESSID:"default"
                    Mode:Master
                    Channel:11
                    Frequency:2.462 GHz (Channel 11)
                    Quality=52/100  Signal level=-46 dBm  
                    Encryption key:on
                    IE: WPA Version 1
                        Group Cipher : TKIP
                        Pairwise Ciphers (1) : TKIP
                        Authentication Suites (1) : PSK
                    Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s
                              9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s
                              48 Mb/s; 54 Mb/s
                    Extra:tsf=000000004284cb93

Describe common problems here, include links to known common problems if on another site