Manual
[root@box]#ethtool -s eth0 speed 10 duplex full autoneg off
[root@box]#ethtool --change eth0 speed 10 duplex full autoneg off

permanen
[root@box]#cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
BOOTPROTO=static
IPADDR=192.168.6.2
NETMASK=255.255.255.252
GATEWAY=192.168.6.1
ONBOOT=yes
METRIC=10
MII_NOT_SUPPORTED=no
USERCTL=yes
DNS1=202.134.1.10
DNS2=202.134.1.7
RESOLV_MODS=no
IPV6INIT=no
IPV6TO4INIT=no
ACCOUNTING=no
ETHTOOL_OPTS="speed 10 duplex full autoneg off"

-ghopal-