# Description:
# This configuration allows you to connect an OPNsense or pfSense router at home and link it to a VPS IP.
# It uses a public IP to redirect traffic to different machines behind the VPS for security reasons rather than opening ports on your home router.

# Prerequisites:
# - Have a VPS server at OVH or Ionos with Debian
# - Install https://github.com/angristan/wireguard-install and generate a client
# - Know the network interface using the 'ip a' command and replace 'ens6' with the correct interface name
# - Know the public IP address or IP addresses of the clients

# Backup the current configuration before modifying it
# Perform this backup before any modification
# cp /etc/wireguard/wg0.conf /etc/wireguard/wg0.conf.bak

# Stopping the WireGuard service before modifying the configuration
# Make sure to stop the service before modifying the configuration
# sudo systemctl stop wg-quick@wg0

# Modify the WireGuard configuration
# Open the configuration file to modify it
# nano /etc/wireguard/wg0.conf
# Delete the section between 'PrivateKey = x' and '### Client opnsense'
# Replace 'your-port' and 'your-public-ip' with actual port and IP information

# WireGuard server side configuration
[Interface]
Address = 10.66.66.1/24, fd42:42:42::1/64
ListenPort = your-port
PrivateKey = x

# iptables rules to apply after setting up the WireGuard interface
PostUp = iptables -I INPUT -p udp --dport your-port -j ACCEPT  # Replace 'your-port' with actual port number
PostUp = iptables -A FORWARD -i wg0 -o ens6 -j ACCEPT
PostUp = iptables -A FORWARD -i ens6 -o wg0 -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
PostUp = iptables -I FORWARD -i wg0 -s 10.66.66.0/24 -d 10.66.66.0/24 -j DROP

PostUp = iptables -t nat -A POSTROUTING -s 10.66.66.2/32 -o ens6 -j SNAT --to-source your-public-ip  # NAT for outgoing traffic from the opnsense client
PostUp = iptables -t nat -A PREROUTING -i ens6 -d your-public-ip -p tcp --dport 80 -j DNAT --to-destination 10.66.66.2:80  # Redirect port 80 to the opnsense client
PostUp = iptables -t nat -A PREROUTING -i ens6 -d your-public-ip -p tcp --dport 443 -j DNAT --to-destination 10.66.66.2:443  # Redirect port 443 to the opnsense client

# iptables rules to remove when deleting the WireGuard interface
PostDown = iptables -D INPUT -p udp --dport your-port -j ACCEPT || true  # Replace 'your-port' with actual port number
PostDown = iptables -D FORWARD -i wg0 -o ens6 -j ACCEPT || true
PostDown = iptables -D FORWARD -i ens6 -o wg0 -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT || true
PostDown = iptables -t nat -D POSTROUTING -s 10.66.66.2/32 -o ens6 -j SNAT --to-source your-public-ip || true
PostDown = iptables -t nat -D PREROUTING -i ens6 -d your-public-ip -p tcp --dport 80 -j DNAT --to-destination 10.66.66.2:80 || true
PostDown = iptables -t nat -D PREROUTING -i ens6 -d your-public-ip -p tcp --dport 443 -j DNAT --to-destination 10.66.66.2:443 || true

### Client opnsense Configuration
[Peer]
PublicKey = x
PresharedKey = x
AllowedIPs = 10.66.66.2/32, fd42:42:42::2/128

# Restart the WireGuard service after modifying the configuration
# sudo systemctl restart wg-quick@wg0
# sudo systemctl status wg-quick@wg0

# OPNsense configuration:
# Follow the steps described in the OPNsense documentation:
# https://docs.opnsense.org
# Configure port forwarding from the OPNsense router to the local IP of the WireGuard client
# For example, forward the port from 192.168.1.x to [local_ip_of_wireguard_client]