vi /etc/init.d/1000Mbs
[bash]#!/bin/sh
ETHTOOL="/usr/sbin/ethtool"
DEV="eth0"
case "$1" in
    start)
        echo -n "Setting eth0 speed 1000 full-duplex…";
        $ETHTOOL -s $DEV speed 1000 duplex full autoneg on;
        echo " done."
        ;;
    stop)
        ;;
esac
exit 0[/bash]
update-rc.d 1000Mbs defaults
SOURCE: http://www.cyberciti.biz/tips/howto-linux-add-ethtool-duplex-settings-permanent.html