Ubuntu – Unable to connect to detected wireless network while connects to wired


I'm using a dual boot pc with windows and ubuntu 10.10. Ubuntu has underwent a fresh installation and now wireless connection is displayed as available but when i connect, it is unable to connect to internet.When i use a wired connection in ubuntu , i can access the internet and it works.The wireless connection works well when i use windows so i don't see a problem with wireless router also my lappy with ubuntu can connect to it .I'm using wired connection just for the time otherwise i use wireless.Some of the output which may be helpful fore reference.


00:00.0 Host bridge: Silicon Integrated Systems [SiS] 671MX
00:01.0 PCI bridge: Silicon Integrated Systems [SiS] SiS AGP Port (virtual PCI-to-PCI bridge)
00:02.0 ISA bridge: Silicon Integrated Systems [SiS] SiS968 [MuTIOL Media IO] (rev  01)
00:02.5 IDE interface: Silicon Integrated Systems [SiS] 5513 [IDE] (rev 01)
00:03.0 USB Controller: Silicon Integrated Systems [SiS] USB 1.1 Controller (rev 0f)
00:03.1 USB Controller: Silicon Integrated Systems [SiS] USB 1.1 Controller (rev 0f)
00:03.3 USB Controller: Silicon Integrated Systems [SiS] USB 2.0 Controller
00:05.0 IDE interface: Silicon Integrated Systems [SiS] SATA Controller / IDE mode (rev 03)
00:06.0 PCI bridge: Silicon Integrated Systems [SiS] PCI-to-PCI bridge
00:07.0 PCI bridge: Silicon Integrated Systems [SiS] PCI-to-PCI bridge
00:0d.0 Communication controller: Conexant Systems, Inc. HSF 56k Data/Fax Modem
00:0f.0 Audio device: Silicon Integrated Systems [SiS] Azalia Audio Controller
00:1f.0 PCI bridge: Silicon Integrated Systems [SiS] PCI-to-PCI bridge
01:00.0 VGA compatible controller: Silicon Integrated Systems [SiS] 771/671 PCIE VGA   Display Adapter (rev 10)
03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E PCI Express Fast Ethernet controller (rev 01)

 lshw -c network

   description: Ethernet interface
   product: RTL8101E/RTL8102E PCI Express Fast Ethernet controller
   vendor: Realtek Semiconductor Co., Ltd.
   physical id: 0
   bus info: pci@0000:03:00.0
   logical name: eth0
   version: 01
   serial: 00:1d:7d:56:84:51
   size: 100MB/s
   capacity: 100MB/s
   width: 64 bits
   clock: 33MHz
   capabilities: pm vpd msi pciexpress bus_master cap_list rom ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation
   configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full ip= latency=0 link=yes multicast=yes port=MII speed=100MB/s
        resources: irq:43 ioport:ec00(size=256) memory:febff000-febfffff memory:febc0000-febdffff
        description: Wireless interface
        physical id: 1
        bus info: usb@1:4
        logical name: wlan0
        serial: 00:21:91:1d:f7:5c
        capabilities: ethernet physical wireless
        configuration: broadcast=yes driver=rt73usb driverversion=2.6.35-22-generic       firmware=N/A link=no multicast=yes wireless=IEEE 802.11bg


     Module                  Size  Used by
     aes_i586                7280  0 
     aes_generic            26875  1 aes_i586
     binfmt_misc             6599  1 
     snd_hda_codec_analog    59649  1 
     arc4                    1165  2 
     snd_hda_intel          22107  2 
     snd_hda_codec          87552  2 snd_hda_codec_analog,snd_hda_intel
     snd_hwdep               5040  1 snd_hda_codec
     snd_pcm                71475  2 snd_hda_intel,snd_hda_codec
     snd_seq_midi            4588  0 
     snd_rawmidi            17783  1 snd_seq_midi
     snd_seq_midi_event      6047  1 snd_seq_midi
     rt73usb                22442  0 
     crc_itu_t               1383  1 rt73usb
     rt2x00usb               9779  1 rt73usb
     snd_seq                47174  2 snd_seq_midi,snd_seq_midi_event
     rt2x00lib              27275  2 rt73usb,rt2x00usb
     led_class               2633  1 rt2x00lib
     mac80211              231541  2 rt2x00usb,rt2x00lib
     snd_timer              19067  2 snd_pcm,snd_seq
     snd_seq_device          5744  3 snd_seq_midi,snd_rawmidi,snd_seq
     ppdev                   5556  0 
     parport_pc             26058  1 
     cfg80211              144470  2 rt2x00lib,mac80211
     snd                    49006  13                     snd_hda_codec_analog,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,snd_rawmidi,snd_seq,snd_timer,snd_seq_device
     soundcore                880  1 snd
     sis_agp                 4123  1 
     snd_page_alloc          7120  2 snd_hda_intel,snd_pcm
     shpchp                 29886  0 
     agpgart                32011  1 sis_agp
     lp                      7342  0 
     parport                31492  3 ppdev,parport_pc,lp
     usbhid                 36882  0 
     hid                    67742  1 usbhid
     usb_storage            40172  0 
     r8169                  36489  0 
     sata_sis                3504  3 
     mii                     4425  1 r8169

     rfkill list wifi

    0: phy0: Wireless LAN
   Soft blocked: no
   Hard blocked: no


http://www.computerandyou.net/2011/10/how-to-solve-no-wireless-network-detected-in-ubuntu-11-10/ Following the above link worked once but when i restart again i'm unable to connect to internet.

Best Answer

While you are connected to wired network:

Open the terminal (Ctrl+Alt+T) and type the following command to install the Synaptic Package Manager:

sudo apt-get install synaptic

  1. Now open the Synaptic Package Manager and search bcm in it. Uninstall or remove any package if already (related to bcm) specially bcmwl-kernel-source

  2. Now install these two packages: b43-fwcutter and firmware-b43-installer.

Disconnect the wired network...restart.

Source: http://www.computerandyou.net/2011/10/how-to-solve-no-wireless-network-detected-in-ubuntu-11-10/

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