This is a follow up blog entry from Using ethtool to check and change Ethernet Card Settings
To force the NIC to use full duplex, 100Mbps, and autonegotiate off, you can
put this in /etc/sysconfig/network-scripts/ifcfg-eth0
--------------------------------------------------------------------------
ETHTOOL_OPTS="speed 100 duplex full autoneg off"
-------------------------------------------------------------------------
This is taken from ethtool from softpanorama.
