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With the newest distribution, beginning yesterday, both of the Ubuntu computers on my network that connect via wireless are randomly dropping the connection several times an hour. The connection re-establishes in a few seconds, but it interrupts downloads, browsing, and updates. The Windows computer connected via Ethernet is not affected by these outages. This didn't happen during the previous several weeks where I had the 12.04 Beta version installed; only beginning yesterday with the new distro. In fact, the connection dropped twice while I was typing this.

sudo lshw -class network returns:

 *-network               
   description: Wireless interface
   product: BCM4321 802.11a/b/g/n
   vendor: Broadcom Corporation
   physical id: 0
   bus info: pci@0000:0c:00.0
   logical name: eth3
   version: 01
   serial: 00:16:cf:c9:36:50
   width: 64 bits
   clock: 33MHz
   capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
   configuration: broadcast=yes driver=wl0 driverversion=5.100.82.38 ip=192.168.0.2 latency=0 multicast=yes wireless=IEEE 802.11abgn
   resources: irq:17 memory:efdfc000-efdfffff memory:e0000000-e00fffff
 *-network
   description: Ethernet interface
   product: BCM4401-B0 100Base-TX
   vendor: Broadcom Corporation
   physical id: 0
   bus info: pci@0000:03:00.0
   logical name: eth2
   version: 02
   serial: 00:18:8b:ab:dc:fd
   size: 10Mbit/s
   capacity: 100Mbit/s
   width: 32 bits
   clock: 33MHz
   capabilities: pm bus_master cap_list ethernet physical mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation
   configuration: autonegotiation=on broadcast=yes driver=b44 driverversion=2.0 duplex=half latency=64 link=no multicast=yes port=twisted pair speed=10Mbit/s
   resources: irq:17 memory:ef9fe000-ef9fffff

lsusb returns:

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 002: ID 413c:a005 Dell Computer Corp. Internal 2.0 Hub
Bus 001 Device 003: ID 0a5c:4500 Broadcom Corp. BCM2046B1 USB 2.0 Hub (part of BCM2046 Bluetooth)
Bus 001 Device 004: ID 413c:8126 Dell Computer Corp. Wireless 355 Bluetooth
Bus 001 Device 005: ID 0a5c:4502 Broadcom Corp. Keyboard (Boot Interface Subclass)
Bus 001 Device 006: ID 0a5c:4503 Broadcom Corp. Mouse (Boot Interface Subclass)

lspci returns:

00:00.0 Host bridge: Intel Corporation Mobile 945GM/PM/GMS, 943/940GML and 945GT Express Memory Controller Hub (rev 03)
00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller (rev 03)
00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller (rev 03)
00:1b.0 Audio device: Intel Corporation N10/ICH 7 Family High Definition Audio Controller (rev 01)
00:1c.0 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 1 (rev 01)
00:1c.1 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 2 (rev 01)
00:1c.3 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 4 (rev 01)
00:1d.0 USB controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #1 (rev 01)
00:1d.1 USB controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #2 (rev 01)
00:1d.2 USB controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #3 (rev 01)
00:1d.3 USB controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #4 (rev 01)
00:1d.7 USB controller: Intel Corporation N10/ICH 7 Family USB2 EHCI Controller (rev 01)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e1)
00:1f.0 ISA bridge: Intel Corporation 82801GBM (ICH7-M) LPC Interface Bridge (rev 01)
00:1f.2 IDE interface: Intel Corporation 82801GBM/GHM (ICH7-M Family) SATA Controller [IDE mode] (rev 01)
00:1f.3 SMBus: Intel Corporation N10/ICH 7 Family SMBus Controller (rev 01)
03:00.0 Ethernet controller: Broadcom Corporation BCM4401-B0 100Base-TX (rev 02)
03:01.0 FireWire (IEEE 1394): Ricoh Co Ltd R5C832 IEEE 1394 Controller
03:01.1 SD Host controller: Ricoh Co Ltd R5C822 SD/SDIO/MMC/MS/MSPro Host Adapter (rev 19)
03:01.2 System peripheral: Ricoh Co Ltd R5C592 Memory Stick Bus Host Adapter (rev 0a)
03:01.3 System peripheral: Ricoh Co Ltd xD-Picture Card Controller (rev 05)
0c:00.0 Network controller: Broadcom Corporation BCM4321 802.11a/b/g/n (rev 01)

rfkill list all returns:

0: brcmwl-0: Wireless LAN
    Soft blocked: no
    Hard blocked: no
1: dell-wifi: Wireless LAN
    Soft blocked: no
    Hard blocked: no
2: dell-bluetooth: Bluetooth
    Soft blocked: no
    Hard blocked: no
3: hci0: Bluetooth
    Soft blocked: no
    Hard blocked: no

I admit, I don't know what to do with any of this. All I know is until yesterday, my connection stayed steady, and with the update, it keeps dropping and reconnecting.

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marked as duplicate by Luis Alvarado Mar 24 '13 at 5:46

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

    
Done! I hope the information is more useful. –  Ian Thomas Healy Apr 28 '12 at 19:11
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3 Answers 3

up vote 4 down vote accepted

I had been having the same issue with the wifi staying connected, but no DNS or routing happening after a few minutes. I would have to restart to get things back up.

What I have done is disable IPV6 and so far, have been connected for 3 hours with no drop. No idea how to prove if this is the solution or if I have just been lucky for the last 3 hours.

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1  
I think your solution fixed my problem, which is very similar (if not identical) to this one! Check it out: askubuntu.com/questions/128024/… –  Wolter Hellmund May 1 '12 at 20:45
    
Disabling IPV6 appears to have solved my issue. Assuming my network remains connected continuously the rest of the evening, I will consider this issue resolved. Thanks, Wolter! –  Ian Thomas Healy May 3 '12 at 3:26
1  
I presume the author means System Settings -> Network -> Wireless -> [select your network(s)] -> Options... -> IPv6 Settings -> Method: Ignore. Please comment if otherwise. –  KomodoDave Oct 7 '12 at 16:51
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There is very high chances that your wi-fi driver is not properly installed. Hit window(meta) button and search for additional drivers on dashboard. Start it and install any extra driver if its indicating to do so.
If that fails then you will have to check which wi-fi driver is installed. For that type ctrl+alt+t and type lspci. you will see list of drivers. Look for Network Controller and reinstall the dirver from synaptic package manager using the code. e.g. bcm43225

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1  
The Broadcom driver is installed and operating. I tried reinstalling it but the problem remains. Do you have any other suggestions? –  Ian Thomas Healy Apr 28 '12 at 19:10
    
Have you been able to install any updates? sudo apt-get update (although judging from your post you know well how to do that :-) –  Clive van Hilten Apr 28 '12 at 19:12
1  
Last night's apt-get update didn't fix anything. I just did another that may have fixed the problem. –  Ian Thomas Healy Apr 28 '12 at 20:01
    
The problem is continuing, unfortunately, with alarming frequency. Every 2-4 minutes now. –  Ian Thomas Healy Apr 29 '12 at 0:40
    
Refer this post of ubuntu forums. And this one to enable backport. –  Ravi Ranjan Apr 29 '12 at 5:36
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Try disabling power management for your WiFi NIC:

example for eth1: iwconfig eth1 power off

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I hate to sound like a complete noob, but how do I know if its eth1? –  Ian Thomas Healy May 1 '12 at 3:34
    
run iwconfig: eth1 IEEE 802.11 Access Point: Not-Associated Link Quality:5 Signal level:229 Noise level:159 Rx invalid nwid:0 invalid crypt:320 invalid misc:0 and look for something like that above. –  BartB May 1 '12 at 6:00
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protected by Community Jul 20 '12 at 20:51

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