I need exact details on how to set NIC speed on a Dell Poweredge 2850.

I need to set speed to 100 FULL.

1) Where do I make change?
2) What is syntax?

I have modified a config file as specified in tid. When I reboot the
server stays at 100 half.

I did find that I can use the following command:
ethtool -s eth0 speed 100 duplex full autoneg off

Except when I reboot it always goes back to 100 half.

Driver being used: e1000

Frustrating that you can't just gui to set the settings.

What commands could I put in YAST NIC options? What config file?