Iptables

#!/bin/bash
# Flush
iptables -t nat -F
iptables -t mangle -F
iptables -F
iptables -X

# Block All
iptables -P OUTPUT DROP
iptables -P INPUT DROP
iptables -P FORWARD DROP

# allow Localhost
iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT

# Make sure you can communicate with any DHCP server
iptables -A OUTPUT -d 255.255.255.255 -j ACCEPT
iptables -A INPUT -s 255.255.255.255 -j ACCEPT

# CHANGED Make sure that you can communicate within your own network. CHANGE 192.168.50.0/24 TO YOUR LOCAL NETWORK
iptables -A INPUT -s #.#.#.#/24 -d #.#.#.#/24 -j ACCEPT
iptables -A OUTPUT -s #.#.#.#/24 -d 192.168.50.0/24 -j ACCEPT

# Allow established sessions to receive traffic:
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

# CHANGED Allow TUN. MAKE SURE YOUR INTERFACE IS CALLED wg-something. THE WG+ IS A WILDCARD.
iptables -A INPUT -i wg+ -j ACCEPT
iptables -A FORWARD -i wg+ -j ACCEPT
iptables -A FORWARD -o wg+ -j ACCEPT
iptables -t nat -A POSTROUTING -o wg+ -j MASQUERADE
iptables -A OUTPUT -o wg+ -j ACCEPT

#CHANGED allow VPN connection. MAKE SURE THE WIREGUARD PORT IS CORRECT, MINE IS 1337
iptables -I OUTPUT 1 -p udp --destination-port 1337 -m comment --comment "Allow VPN connection" -j ACCEPT

# Block All
iptables -A OUTPUT -j DROP
iptables -A INPUT -j DROP
iptables -A FORWARD -j DROP

# Log all dropped packages, debug only.

iptables -N logging
iptables -A INPUT -j logging
iptables -A OUTPUT -j logging
iptables -A logging -m limit --limit 2/min -j LOG --log-prefix "IPTables general: " --log-level 7
iptables -A logging -j DROP

echo "saving"
iptables-save > /etc/iptables.rules
echo "done"
#echo 'openVPN - Rules successfully applied, we start "watch" to verify IPtables in realtime (you can cancel it as usual CTRL + c)'
#sleep 3
#watch -n 0 "sudo iptables -nvL"