gw_down.sh

#!/bin/bash
IF_IN="eth0"
IF_OUT="wlan0"
SUB="192.168.100"

echo "[+] Bringing interface ${IF_IN} down"
ip addr del ${SUB}.1/24 dev ${IF_IN}
ip link set dev ${IF_IN} down

echo "[+] Removing iptable rules"
iptables -t nat -D POSTROUTING -s ${SUB}.0/24 -j MASQUERADE
iptables -D FORWARD -o ${IF_IN} -i ${IF_OUT} -s ${SUB}.0/24 -m conntrack --ctstate NEW -j ACCEPT
iptables -D FORWARD -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT

echo "[+] Stopping DHCP server"
killall dhcpd

echo "[+] Done"