I have a new computer with a fresh Ubuntu 12.04 installation. While everything else seems to be working fine, I am having trouble with the network connectivity. The computer recognizes the card, and the drivers are installed just fine. Also, Ubuntu recognizes the connections and is able to get the correct configurations over DHCP. However, I can't access anything over the internet. A dmesg gives the following results, which I believe to be related:
dmesg
[ 1988.749847] atl1c 0000:05:00.0: atl1c: eth0 NIC Link is Down
[ 1991.012964] atl1c 0000:05:00.0: atl1c: eth0 NIC Link is Up<100 Mbps Full Duplex>
[ 1992.041493] atl1c 0000:05:00.0: atl1c: eth0 NIC Link is Down
[ 1994.157886] atl1c 0000:05:00.0: atl1c: eth0 NIC Link is Up<100 Mbps Full Duplex>
[ 1995.186466] atl1c 0000:05:00.0: atl1c: eth0 NIC Link is Down
[ 1997.543924] atl1c 0000:05:00.0: atl1c: eth0 NIC Link is Up<100 Mbps Full Duplex>
[ 1998.572955] atl1c 0000:05:00.0: atl1c: eth0 NIC Link is Down
[ 2000.709857] atl1c 0000:05:00.0: atl1c: eth0 NIC Link is Up<100 Mbps Full Duplex>
[ 2001.738376] atl1c 0000:05:00.0: atl1c: eth0 NIC Link is Down
[ 2003.875841] atl1c 0000:05:00.0: atl1c: eth0 NIC Link is Up<100 Mbps Full Duplex>
[ 2004.903859] atl1c 0000:05:00.0: atl1c: eth0 NIC Link is Down
[ 2007.073192] atl1c 0000:05:00.0: atl1c: eth0 NIC Link is Up<100 Mbps Full Duplex>
[ 2008.102022] atl1c 0000:05:00.0: atl1c: eth0 NIC Link is Down
My network card is an Atheros AR8151, onboard of a Gigabyte GA-Z77X-UD3H MoBo. I am sure it is not a hardware problem, since my Windows installation is the same machine is working just fine.
What steps should I take to try fixing this issue?
Following are other potentially useful information.
ifconfig eth0
eth0 Link encap:Ethernet HWaddr 90:2b:34:30:c2:8c
inet addr:192.168.2.107 Bcast:192.168.2.255 Mask:255.255.255.0
inet6 addr: fe80::922b:34ff:fe30:c28c/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:6 errors:0 dropped:0 overruns:0 frame:0
TX packets:3 errors:0 dropped:0 overruns:0 carrier:1350
collisions:0 txqueuelen:1000
RX bytes:2072 (2.0 KB) TX bytes:774 (774.0 B)
Interrupt:47
lspci -v
05:00.0 Ethernet controller: Atheros Communications Inc. AR8151 v2.0 Gigabit Ethernet (rev c0)
Subsystem: Giga-byte Technology Device e000
Flags: bus master, fast devsel, latency 0, IRQ 47
Memory at f7d00000 (64-bit, non-prefetchable) [size=256K]
I/O ports at e000 [size=128]
Capabilities:
Kernel driver in use: atl1c
Kernel modules: atl1c
sudo lshw -class network
*-network
description: Ethernet interface
product: AR8151 v2.0 Gigabit Ethernet
vendor: Atheros Communications Inc.
physical id: 0
bus info: pci@0000:05:00.0
logical name: eth0
version: c0
serial: 90:2b:34:30:c2:8c
capacity: 1Gbit/s
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress vpd bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
configuration: autonegotiation=on broadcast=yes driver=atl1c driverversion=1.0.1.0-NAPI firmware=N/A ip=192.168.2.107 latency=0 link=no multicast=yes port=twisted pair
resources: irq:47 memory:f7d00000-f7d3ffff ioport:e000(size=128)
ping www.google.com
ping: unknown host www.google.com
ping 74.125.155.103
PING 74.125.155.103 (74.125.155.103) 56(84) bytes of data.
From 192.168.2.107 icmp_seq=1 Destination Host Unreachable
From 192.168.2.107 icmp_seq=2 Destination Host Unreachable
From 192.168.2.107 icmp_seq=3 Destination Host Unreachable
(And so forth)
