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Last week, I experienced a problem with wired connection on my Ubuntu 12.04 installation. I'm in a college dorm and I have to connect to the dorm network using 802.1x security. It worked great on both my Windows 7 and Ubuntu 12.04 installations (dual boot) until the connection started failing on Ubuntu. It would start to try to connect (Network Manager icon going ''up and down'') and after 30-40 seconds a window would jump out, asking me to enter my username and password for 802.1x. When I did, it would just keep trying to connect and after 30-40 seconds the same window would jump out.

My Ubuntu 12.04 install was fairly fresh and I planned on upgrading to 13.04 anyway, so I removed 12.04 installation and installed 13.04. Everything went smoothly, but networking issue remains.

Here is my ifconfig and lshw:


eth0      Link encap:Ethernet  HWaddr ac:22:0b:0f:eb:9f  
          inet6 addr: fe80::ae22:bff:fe0f:eb9f/64 Scope:Link
          RX packets:3 errors:0 dropped:0 overruns:0 frame:0
          TX packets:56 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:180 (180.0 B)  TX bytes:11073 (11.0 KB)

lo        Link encap:Local Loopback  
          inet addr:  Mask:
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:105 errors:0 dropped:0 overruns:0 frame:0
          TX packets:105 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:9362 (9.3 KB)  TX bytes:9362 (9.3 KB)


       description: Ethernet interface
       product: RTL8111/8168 PCI Express Gigabit Ethernet controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0.2
       bus info: pci@0000:04:00.2
       logical name: eth0
       version: 0a
       serial: ac:22:0b:0f:eb:9f
       size: 10Mbit/s
       capacity: 1Gbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl8411-1_0.0.3 06/18/12 latency=0 link=yes multicast=yes port=MII speed=10Mbit/s
       resources: irq:42 ioport:d000(size=256) memory:f2104000-f2104fff memory:f2100000-f2103fff

EDIT: After some additional googling, I discovered that Realtek 8168 is known for having problems with Linux:

I downloaded latest driver from Realtek's website (version 8.036.00), installed it according to readme file found with it, everything ran smoothly... but it's still not working.

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up vote 2 down vote accepted

Press Ctrl+Alt+T and then enter this in the command prompt :

echo on | sudo tee /sys/class/net/eth0/device/power/control

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did this work in addition to updating the driver? I did this and still had some dropped connections – bjackfly Oct 22 '13 at 18:06
It did. However, if it doesnt work, you still can restart your network services using sudo /etc/init.d/networking restart – kelvinelove Oct 22 '13 at 20:17

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