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:
ifconfig eth0 Link encap:Ethernet HWaddr ac:22:0b:0f:eb:9f inet6 addr: fe80::ae22:bff:fe0f:eb9f/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 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:127.0.0.1 Mask:255.0.0.0 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) lshw *-network 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: http://www.twm-kd.com/linux/realtek-rtl81688111e-and-ubuntu-linux/ http://unixblogger.wordpress.com/2011/10/18/the-pain-of-an-realtek-rtl8111rtl8168-ethernet-card/
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.