Hi there all. I had a serious problem with my NIC and would like to share the solution 
The problem started already on Ubuntu 9.10 x64, when my network interface name kept changing after each reboot, this is original post [ubuntu] Why does my network interface name change? - Ubuntu Forums](http://ubuntuforums.org/showthread.php?t=1484063). I couldn’t solve this issue and decided to live with it, since I didn’t really care about the interface name, all I wanted was to assign fixed ip to my box. After a while I decided to put suse 11.2 x64 on the very same box, and I got the same problem, after each reboot my NIC got a different MAC address and kernel detected a new unconfigured network interface, and I had to define static ip after each reboot, grrrrrr. Doing a little research on this I found out:
dmesg |grep Mac
5.988576] forcedeth 0000:00:07.0: Invalid Mac address detected: 0b:68:66:ea:0f:00
5.988590] forcedeth 0000:00:07.0: Please complain to your hardware vendor. Switching to a random MAC
the NIC is nvidia on Gigabyte mobo
lspci -nn |grep Eth
00:07.0 Bridge [0680]: nVidia Corporation MCP61 Ethernet [10de:03ef] (rev a2)
googling around I found the solution is to write a rule in one of the files in /etc/udev/rules.d/ I picked up 70-persistent-net.rules, it may work with some other also, don’t know didn’t try. So after the change I made the part of the file now looks like
#SUBSYSTEM=="net",ACTION=="add",DRIVERS=="?*",ATTR{address}#=="00:00:6c:ea:75:3e",ATTR{type}=="1",#KERNEL=="eth*",NAME="eth0"
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ID=="0000:00:07.0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"
so the catch is to change the reference to the NIC from the strange MAC address to pci bus id. More help can be found here How to fix invalid MAC address on Nforce MCP network controller [Andy’s Wiki]