I have installed Ubuntu 12.10 (64bits) (3.5.0-18 kernel) on an ASUS N56VM and the ethernet card isn't working. Wireless card works okay. The card is Atheros Communications Inc. AR8161 Gigabit Ethernet [1969:1091] (rev 10).
I have read that there's a workaround for 12.04 but not for 12.10.
Additional Info:
$ lspci -nnk | grep -i ethernet
04:00.0 Ethernet controller [0200]: Atheros Communications Inc. AR8161 Gigabit Ethernet [1969:1091] (rev 10)
$ ifconfig eth0
eth0: error fetching interface information: Device not found
$ ifconfig -a
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:1138 errors:0 dropped:0 overruns:0 frame:0
TX packets:1138 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:115837 (115.8 KB) TX bytes:115837 (115.8 KB)
wlan0 Link encap:Ethernet HWaddr e0:b9:a5:f9:ba:02
inet addr:192.168.0.102 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::e2b9:a5ff:fef9:ba02/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:8911 errors:0 dropped:0 overruns:0 frame:0
TX packets:7175 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:7837367 (7.8 MB) TX bytes:1063488 (1.0 MB)