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I recently dual installed Linux next to Windows 7. Everything worked fine for the first couple days. Then I decided to upgrade from 11.10 to 12.04. I think the installation got hung up at the end because when the computer rebooted it froze and I had to force a shutdown with the power button.

After that things got strange. My wifi and ethernet have not been working, even when I select different versions of the kernel from the GRUB menu. It's a hassle going between Windows to get online and troubleshoot to revert back to Linux to execute commands. Today I tried reinstalling 11.10 over 12.04, by selecting the Ubuntu option to "upgrade from 12.04 to 11.10. Still have the problem, but hopefully someone can help.

It looks like wlan0 and eth0 aren't working. I can't see either wlan0 or eth0 (only lo) with just the normal "ifconfig" command. I am also unable to open the Networking section under System Settings.

ifconfig -a
eth0      Link encap:Ethernet  HWaddr b8:70:f4:2c:2b:9a  
          BROADCAST 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)
          Interrupt:41 Base address:0x8000 

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:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

wlan0     Link encap:Ethernet  HWaddr ac:81:12:a4:7e:a3  
          BROADCAST 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)

lspci | grep Ether
06:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E PCI Express Fast Ethernet controller (rev 02)

sudo lshw -c NET
PCI (sysfs)  
  *-network DISABLED      
       description: Wireless interface
       product: BCM4313 802.11b/g/n Wireless LAN Controller
       vendor: Broadcom Corporation
       physical id: 0
       bus info: pci@0000:05:00.0
       logical name: wlan0
       version: 01
       serial: ac:81:12:a4:7e:a3
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=brcmsmac driverversion=3.0.0-26-generic firmware=N/A latency=0 link=no multicast=yes wireless=IEEE 802.11bgn
       resources: irq:17 memory:d6400000-d6403fff
  *-network DISABLED
       description: Ethernet interface
       product: RTL8101E/RTL8102E PCI Express Fast Ethernet controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:06:00.0
       logical name: eth0
       version: 02
       serial: b8:70:f4:2c:2b:9a
       size: 100Mbit/s
       capacity: 100Mbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix vpd 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 firmware=N/A latency=0 link=no multicast=yes port=MII speed=100Mbit/s
       resources: irq:41 ioport:2000(size=256) memory:d2410000-d2410fff memory:d2400000-d240ffff memory:d2420000-d243ffff

an attempt to activate eth0
sudo lshw -enable eth0
*-network
                description: Ethernet interface
                product: RTL8101E/RTL8102E PCI Express Fast Ethernet controller
                vendor: Realtek Semiconductor Co., Ltd.
                physical id: 0
                bus info: pci@0000:06:00.0
                logical name: eth0
                version: 02
                serial: b8:70:f4:2c:2b:9a
                size: 100Mbit/s
                capacity: 100Mbit/s
                width: 64 bits
                clock: 33MHz
                capabilities: pm msi pciexpress msix vpd 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 firmware=N/A latency=0 link=yes multicast=yes port=MII speed=100Mbit/s

Do I need to download a different program to take over the networking in ubuntu if the default isn't working? Why would the fresh install (keeping personal folders) not solve the problem?

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1 Answer

Boot into Ubuntu and go to terminal and type this command to reset all hardware switches for your networking:

sudo rfkill list all

Now reboot and things should start working again :)

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I tried using a different kernel version and this time things works for some reason. Might have been a driver or kernel issue with the built in network center. Will keep your suggestion in mind for the future. –  Anon Oct 2 '12 at 5:17
    
Please specify the failing and working kernel versions –  waltinator Aug 6 '13 at 0:55
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