edit this file: /etc/sysconfig/network-scr
ipts/ifcfg
-eth0
$ cat /etc/sysconfig/network-scr
ipts/ifcfg
-eth0
# Realtek Semiconductor Co., Ltd. RTL-8169 Gigabit Ethernet
DEVICE=eth0
HWADDR=00:14:6C:8E:B6:12
MORE INFO:
http://www.linuxhomenetworking.com/wiki/index.php/Quick_HOWTO_:_Ch03_:_Linux_Networking