Servidor DHCP

Boa noite galera estou com essas configurações em meu servidor, porem eu não consigo liberar a internet e meu servidor não libera IP automaticamente! Será que alguém poderia me ajudar!

sudo vim /etc/network/interfaces

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp

auto eth1
iface eth1 inet static

address 10.0.0.1
netmask 255.255.0.0
network 10.0.0.0
broadcast 10.0.255.255

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$ sudo vim /etc/sysctl.conf

net.ipv4.ip_forward=1

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$ sudo vim /etc/init.d/internet

#!/bin/bash

iniciar(){
modprobe iptable_nat
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
}

parar(){
iptables -F -t nat
}

case "$1" in
"start") iniciar ;;
"stop") parar ;;
"restart") parar; iniciar ;;
*) echo "Use os parâmetros start ou stop"
esac

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$ sudo vim /etc/dhcp/dhcpd.conf

ddns-update-style none;
option domain-name "ubuntu";
option domain-name-servers 8.8.4.4, 8.8.8.8.8;

default-lease-time 600;
max-lease-time 7200;

authoritative;

log-facility local7;

subnet 10.0.0.0 netmask 255.255.0.0 {
range 10.0.0.2 10.0.255.255;
option routers 10.0.0.1;
option broadcast-address 10.0.255.255;

}

##################

$ sudo vim /etc/default/isc-dhcp-server

INTERFACES="eth1

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