install ubuntu without cd

netboot

install bootp
vim /etc/bootptab

client:\
ha="00:22:15:75:BC:B1":\
ip=192.168.3.107:\
gw=192.168.3.1:\
sm=255.255.255.0:\
td=/: hd=/: bf=pxelinux.0

bootp start file

vDaemon=bootpd
vCd=/var/lib/tftpboot

Start () {
    echo -n "Starting $vDaemon: default current directory is at $vCd ... :"
    /usr/sbin/$vDaemon -d 4 -c $vCd >/tmp/$vDaemon.log 2>/tmp/$vDaemon.err &
    sleep 1
    Status
}

Stop () {
        echo "Stopping $vDaemon ..."
    kill `pidof $vDaemon`
}

Reload () {
    if [ "`pidof $vDaemon`" ] ; then
        echo "Reloading config file for $vDaemon ..."
        kill -HUP "`pidof $vDaemon`"
    fi
    Status
}

Status () {
    vPid="`pidof $vDaemon`"
    if [ "$vPid" ] ; then
        echo "$vDaemon running, pid=$vPid"
    else
        echo "$vDaemon not running"
    fi
}

case "$1" in
    start)      Start ;;
    stop)       Stop ;;
    reload) Reload ;;
    restart) Stop ; sleep 2; Start ;;
    status) Status ;;
    ""|*) echo `basename $0` parameter: start stop status reload or restart ;;
esac