#!/bin/sh
# Enable IP forwarding
echo "net.ipv4.ip_forward=1" >> /etc/sysctl.conf
sysctl -p
# Install required packages
apk add iptables iptables-openrc dnsmasq
# Configure iptables for NAT
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
iptables -A FORWARD -i eth1 -j ACCEPT
# Save iptables rules
mkdir -p /etc/iptables
iptables-save > /etc/iptables/rules-save
# Enable iptables service at boot
rc-update add iptables default
# Assign static IP to eth1
cat <<EOF > /etc/network/interfaces
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet dhcp
auto eth1
iface eth1 inet static
address 192.168.100.1
netmask 255.255.255.0
EOF
# Enable networking service at boot
rc-update add networking default
# Configure dnsmasq
cat <<EOF > /etc/dnsmasq.conf
interface=eth1
dhcp-range=192.168.100.50,192.168.100.150,12h
dhcp-option=3,192.168.100.1
dhcp-option=6,8.8.8.8
EOF
# Enable and start dnsmasq
rc-update add dnsmasq default
rc-service dnsmasq restart
echo "Internet sharing setup complete and persistent across reboots."
