i have to change my ethernet card's MAC addr ,to avoid changing it every time after reboot ,i add the
ifconfig commands:
ifconfig eth0 down
ifconfig eth0 hw ether XX:XX:XX:XX:XX:XX
ifconfig eth0 up
to the file
/etc/rc.d/rc.local
However it dosen't work .That's one thing i'am puzzled ,and the following is another :
if i run the ifconfig command directly in the console ,it dosen't work!
However, the redhat-config-network can work only if the 'ifconfig' commands have been added to the file /etc/rc.d/rc.local.
So how does redhat-config-network do the job changing MAC address and give such a puzzle ??

Thanks

You probably need to edit your ifcfg for the interface. For etho it is:

/etc/sysconfig/network-scripts/ifcfg-eth0

On my RedHat AS3 this looks like:
# Intel Corp.|82541EI Gigabit Ethernet Controller
DEVICE=eth0
BOOTPROTO=none
BROADCAST=xx.xx.xx.255
HWADDR=xx:xx:xx:xx:xx:xx
IPADDR=xx.xx.xx.xx
NETMASK=255.255.255.0
NETWORK=xx.xx.xx.xx
ONBOOT=yes
TYPE=Ethernet
USERCTL=no
PEERDNS=no
GATEWAY=xx.xx.xx.1
ETHTOOL_OPTS="autoneg off speed 100 duplex full"


the HWADDR line is where the MAC address would be. You can run ifdown eth0 then ifup eth0 to stop and start just this interface.

The ETHTOOL_OPTS is something I added so it turns off autonegotiate and hard sets the speed to 100 and the duplex to full.