First commit

FIREWALL.md

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+# Firewall Configuration with nftables
+
+## Overview
+This setup uses nftables (the modern successor to iptables) to secure the WireGuard VPN server.
+
+## Configuration Details
+
+### nftables Settings
+- **Dual-stack Support**: Single ruleset handles both IPv4 and IPv6
+- **Default Incoming Policy**: Drop
+- **Default Outgoing Policy**: Accept
+- **Table Type**: `inet` (handles both IPv4 and IPv6)
+
+### Allowed Services
+| Service | Port | Protocol | Description |
+|---------|------|----------|-------------|
+| SSH | 22 | TCP | Remote server access |
+| WireGuard | 51820 | UDP | VPN traffic |
+
+### How It Works
+The firewall setup uses nftables with a unified architecture:
+
+1. **inet Table**: Single table for both IPv4 and IPv6 filter rules
+   - `input` chain: Filters incoming traffic
+   - `forward` chain: Controls packet forwarding
+   - `output` chain: Manages outgoing traffic
+
+2. **NAT Tables**: Separate tables for IPv4 and IPv6 masquerading
+   - `ip nat` table: IPv4 NAT masquerade for VPN traffic
+   - `ip6 nat` table: IPv6 NAT masquerade for VPN traffic
+
+3. **Rules**:
+   - Loopback traffic allowed
+   - Established/related connections allowed
+   - Invalid packets dropped
+   - SSH and WireGuard ports allowed
+   - ICMP/ICMPv6 for basic connectivity
+   - Forwarding from wg0 interface allowed
+   - NAT masquerade for internet access
+
+### Advantages over iptables/UFW
+- Single configuration file for IPv4/IPv6
+- More efficient packet processing
+- Better performance on high-traffic systems
+- Modern, actively maintained
+
+## Management Commands
+
+### View firewall rules
+```bash
+sudo nft list ruleset
+```
+
+### View specific chain
+```bash
+sudo nft list chain inet wireguard input
+```
+
+### Enable/disable firewall
+```bash
+sudo nftables-firewall enable
+sudo nftables-firewall disable
+```
+
+### Allow additional ports
+```bash
+sudo nftables-firewall allow 80/tcp
+sudo nftables-firewall allow 443/tcp
+```
+
+### Allow from specific IP
+```bash
+# IPv4
+sudo nftables-firewall allow from 192.168.1.100
+
+# IPv6
+sudo nftables-firewall allow from 2001:db8::/32
+
+# CIDR range
+sudo nftables-firewall allow from 192.168.1.0/24
+```
+
+### Delete a rule
+```bash
+# List rules with numbers
+sudo nft -a list chain inet wireguard input
+
+# Delete by handle number
+sudo nftables-firewall delete <handle_number>
+```
+
+### Reload firewall
+```bash
+sudo nftables-firewall reload
+```
+
+### Manually add a rule
+```bash
+# Allow TCP port 8080
+sudo nft add rule inet wireguard input tcp dport 8080 accept
+
+# Allow UDP port 53
+sudo nft add rule inet wireguard input udp dport 53 accept
+```
+
+## Important Notes
+
+1. **SSH is always allowed**: The setup explicitly allows SSH to prevent lockout
+2. **IPv4/IPv6 unified**: Single configuration handles both protocols
+3. **Persistent rules**: nftables rules are saved in `/etc/nftables.d/wireguard.conf`
+4. **No UFW dependency**: Direct nftables implementation
+5. **Automatic on boot**: nftables service starts automatically
+
+## Troubleshooting
+
+### Check if nftables is active
+```bash
+sudo nft list ruleset
+```
+
+### Check service status
+```bash
+sudo systemctl status nftables
+```
+
+### View blocked connections
+```bash
+# Count packets by rule
+sudo nft -a list ruleset | grep -i counter
+
+# Monitor connections
+sudo conntrack -L
+```
+
+### Test connectivity from client
+```bash
+# Test WireGuard port (from another machine)
+nc -zuv velkhana.calmcacil.dev 51820
+```
+
+### Verify forwarding
+```bash
+# Check WireGuard interface
+ip addr show wg0
+
+# Check forwarding is enabled
+sysctl net.ipv4.ip_forward
+sysctl net.ipv6.conf.all.forwarding
+```
+
+### Verify NAT is working
+```bash
+# Check NAT rules
+sudo nft list table ip nat
+sudo nft list table ip6 nat
+```
+
+### Reset to defaults
+```bash
+# Flush all rules
+sudo nft flush ruleset
+
+# Reload from config
+sudo nftables-firewall reload
+```
+
+### Debug with counters
+```bash
+# Add counters to see rule hits
+sudo nft add rule inet wireguard input counter accept
+
+# View rule statistics
+sudo nft list ruleset
+```
+
+## Advanced Usage
+
+### Logging dropped packets
+```bash
+# Add logging to input chain
+sudo nft add rule inet wireguard input log prefix "nft drop: " drop
+
+# View logs
+sudo journalctl -k | grep "nft drop"
+```
+
+### Rate limiting
+```bash
+# Rate limit SSH connections
+sudo nft add rule inet wireguard input tcp dport 22 ct state new limit rate 5/minute accept
+```
+
+### Port knocking (simplified)
+```bash
+# Three-step port knock on ports 1000, 2000, 3000 opens SSH
+sudo nft add rule inet wireguard input tcp dport 1000 ct state new update @knock { ip saddr timeout 60s } accept
+sudo nft add rule inet wireguard input tcp dport 2000 ip saddr @knock update @knock { ip saddr timeout 60s } accept
+sudo nft add rule inet wireguard input tcp dport 3000 ip saddr @knock update @knock { ip saddr timeout 60s } tcp dport 22 accept
+```
+
+## Configuration Files
+
+### Main configuration
+```
+/etc/nftables.d/wireguard.conf
+```
+
+### System service
+```
+/etc/systemd/system/nftables.service
+```
+
+### Management script
+```
+/usr/local/sbin/nftables-firewall
+```
+
+## Migration from UFW
+
+If migrating from a UFW-based setup:
+
+| UFW Command | nftables Equivalent |
+|-------------|---------------------|
+| `ufw status` | `nft list ruleset` |
+| `ufw enable` | `nftables-firewall enable` |
+| `ufw disable` | `nftables-firewall disable` |
+| `ufw allow 80/tcp` | `nft add rule inet wireguard input tcp dport 80 accept` |
+| `ufw delete allow 80/tcp` | `nft delete rule inet wireguard input handle <num>` |
+| `ufw reset` | `nft flush ruleset && nftables-firewall reload` |

README.md

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+# WireGuard VPN Setup for Debian 13
+
+## Overview
+Personal WireGuard VPN server with IPv4/IPv6 support, client management via `/etc/wireguard/peer.d/`, designed for 1 CPU / 1GB RAM VPS.
+
+## Configuration
+- **Server Domain**: velkhana.calmcacil.dev
+- **Port**: 51820
+- **VPN IPv4 Range**: 10.10.69.0/24
+- **VPN IPv6 Range**: fd69:dead:beef:69::/64
+- **DNS**: 8.8.8.8, 8.8.4.4 (Google)
+- **Server-side peer configs**: /etc/wireguard/peer.d/*.conf (loaded dynamically)
+- **Client-side configs**: /etc/wireguard/clients/*.conf (for distribution)
+
+## Installation
+
+### 1. Upload files to VPS
+```bash
+scp install-wireguard.sh wg-client-manager calmcacil@velkhana.calmcacil.dev:~/
+```
+
+### 2. Run installation
+```bash
+chmod +x ~/install-wireguard.sh ~/wg-client-manager
+sudo ~/install-wireguard.sh
+```
+
+### 3. Install client manager
+```bash
+sudo mv ~/wg-client-manager /usr/local/sbin/
+sudo chmod +x /usr/local/sbin/wg-client-manager
+```
+
+## Usage
+
+### Dynamic client loading
+WireGuard automatically loads clients from `/etc/wireguard/peer.d/`:
+- Add/remove client configs in `/etc/wireguard/peer.d/*.conf`
+- Run `sudo /usr/local/sbin/wg-load-clients` to reload
+- Changes are applied immediately without restarting
+
+### Add a new client
+```bash
+sudo /usr/local/sbin/wg-client-manager add myphone
+```
+This creates:
+- Server config in `/etc/wireguard/peer.d/myphone.conf`
+- Client config in `/etc/wireguard/clients/myphone.conf`
+- QR code in `/etc/wireguard/clients/myphone.qr`
+
+### List all clients
+```bash
+sudo /usr/local/sbin/wg-client-manager list
+```
+
+### Show client config
+```bash
+sudo /usr/local/sbin/wg-client-manager show myphone
+```
+
+### Show QR code
+```bash
+sudo /usr/local/sbin/wg-client-manager qr myphone
+```
+
+### Remove a client
+```bash
+sudo /usr/local/sbin/wg-client-manager remove myphone
+```
+
+## Server Management
+
+### Check WireGuard status
+```bash
+sudo wg show
+```
+
+### Check service status
+```bash
+sudo systemctl status wg-quick@wg0
+```
+
+### Restart WireGuard
+```bash
+sudo systemctl restart wg-quick@wg0
+```
+
+### Reload clients (automatic on add/remove)
+```bash
+sudo /usr/local/sbin/wg-load-clients
+```
+
+### Firewall management
+The setup configures nftables with:
+- Dual-stack IPv4/IPv6 support in a single ruleset
+- Default drop incoming, accept outgoing
+- SSH access allowed (port 22)
+- WireGuard allowed (UDP 51820)
+- Forwarding from wg0 interface allowed
+- NAT masquerade for VPN internet access
+
+View firewall rules:
+```bash
+sudo nft list ruleset
+```
+
+Enable/disable firewall:
+```bash
+sudo nftables-firewall disable
+sudo nftables-firewall enable
+```
+
+Allow additional ports if needed:
+```bash
+sudo nftables-firewall allow 80/tcp    # HTTP
+sudo nftables-firewall allow 443/tcp   # HTTPS
+```
+
+## Manual Client Configuration
+
+To manually add a client, create a file in `/etc/wireguard/peer.d/`:
+
+```ini
+[Peer]
+# mydevice
+PublicKey = <client_public_key>
+AllowedIPs = 10.10.69.2/32, fd69:dead:beef:69::2/128
+```
+
+Then run:
+```bash
+sudo /usr/local/sbin/wg-load-clients
+```
+
+## Client Setup
+
+### Importing the config
+- **Desktop**: Import `/etc/wireguard/clients/<name>.conf` into WireGuard app
+- **Mobile**: Scan QR code with WireGuard app, or import config file
+
+### Test connectivity
+```bash
+# On client
+ping 10.10.69.1
+ping -6 fd69:dead:beef:69::1
+
+# Check your IP
+curl -4 https://ifconfig.me
+curl -6 https://ifconfig.me
+```
+
+## Troubleshooting
+
+### Check firewall
+```bash
+sudo nft list ruleset
+```
+
+### Check IP forwarding
+```bash
+sysctl net.ipv4.ip_forward
+sysctl net.ipv6.conf.all.forwarding
+```
+
+### View logs
+```bash
+sudo journalctl -u wg-quick@wg0 -f
+```
+
+### Check client directory
+```bash
+ls -la /etc/wireguard/peer.d/
+```
+
+### Manual reload if needed
+```bash
+sudo /usr/local/sbin/wg-load-clients
+```
+
+## Notes
+- `/etc/wireguard/peer.d/` - Server-side peer configs, loaded automatically by wg-load-clients
+- `/etc/wireguard/clients/` - Client-side configs (import to WireGuard apps) and QR codes
+- Clients are automatically reloaded when added/removed
+- IPv4 and IPv6 NAT are configured (MASQUERADE)
+- nftables firewall is configured with dual-stack IPv4/IPv6 support
+- Single nftables ruleset handles both IPv4 and IPv6
+- SSH (port 22) and WireGuard (UDP 51820) are allowed by default
+- Keepalive is set to 25 seconds for better stability
+- Server private keys are stored in `/etc/wireguard/server_private.key`
+- Server public key is displayed after installation
+- Use `nftables-firewall` script for easy firewall management

VALIDATION.md

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+# Firewall Validation Report
+
+## Migration from UFW/iptables to nftables
+
+### Changes Made
+
+#### 1. Package Installation
+**Before**: `apt-get install -y wireguard wireguard-tools qrencode iptables ufw`
+**After**: `apt-get install -y wireguard wireguard-tools qrencode nftables`
+
+**Rationale**:
+- Removed iptables and ufw dependencies
+- Added nftables package (modern successor to iptables)
+- Cleaner, more efficient packet filtering
+
+#### 2. Firewall Configuration
+**Before**: UFW configuration with iptables/ip6tables rules
+```bash
+ufw default deny incoming
+ufw default allow outgoing
+ufw allow ssh
+ufw allow 51820/udp
+```
+
+**After**: nftables with unified dual-stack rules
+```nft
+table inet wireguard {
+    chain input {
+        type filter hook input priority 0; policy drop;
+        iif lo accept
+        ct state established,related accept
+        ct state invalid drop
+        tcp dport 22 accept
+        udp dport 51820 accept
+        icmp type { echo-request, echo-reply } accept
+        icmpv6 type { echo-request, echo-reply, nd-neighbor-solicit, nd-neighbor-advert } accept
+    }
+    chain forward {
+        type filter hook forward priority 0; policy drop;
+        ct state established,related accept
+        iif wg0 accept
+        oif wg0 accept
+    }
+    chain output {
+        type filter hook output priority 0; policy accept;
+    }
+}
+table ip nat {
+    chain postrouting {
+        type nat hook postrouting priority 100; policy accept;
+        oifname eth0 ip saddr 10.10.69.0/24 masquerade
+    }
+}
+table ip6 nat {
+    chain postrouting {
+        type nat hook postrouting priority 100; policy accept;
+        oifname eth0 ip6 saddr fd69:dead:beef:69::/64 masquerade
+    }
+}
+```
+
+**Rationale**:
+- Single `inet` table handles both IPv4 and IPv6
+- More concise and readable configuration
+- Better performance on high-traffic systems
+- No need for separate UFW route rules
+
+#### 3. WireGuard PostUp/PostDown Rules
+**Before**: Multiple iptables/ip6tables/ufw commands
+```ini
+PostUp = iptables -A FORWARD -i wg0 -j ACCEPT; iptables -A FORWARD -o wg0 -j ACCEPT; iptables -t nat -A POSTROUTING -o eth0 -s 10.10.69.0/24 -j MASQUERADE; ufw route allow in on wg0 out on eth0; ufw route allow in on eth0 out on wg0
+PostDown = iptables -D FORWARD -i wg0 -j ACCEPT; iptables -D FORWARD -o wg0 -j ACCEPT; iptables -t nat -D POSTROUTING -o eth0 -s 10.10.69.0/24 -j MASQUERADE; ufw route delete allow in on wg0 out on eth0; ufw route delete allow in on eth0 out on wg0
+```
+
+**After**: No PostUp/PostDown needed
+```ini
+# No PostUp/PostDown needed - nftables rules are persistent
+```
+
+**Rationale**:
+- nftables rules are persistent (loaded at boot via service)
+- No need for dynamic rule addition/removal
+- Cleaner WireGuard configuration
+- All firewall logic in one place
+
+#### 4. Management Script
+**New**: `/usr/local/sbin/nftables-firewall`
+```bash
+nftables-firewall status    # Show firewall rules
+nftables-firewall enable    # Enable firewall
+nftables-firewall disable   # Disable firewall
+nftables-firewall allow 80/tcp    # Allow TCP port 80
+nftables-firewall delete <num>    # Delete rule by number
+nftables-firewall reload    # Reload firewall rules
+```
+
+**Rationale**:
+- Provides UFW-like interface for nftables
+- Easier transition for users familiar with UFW
+- Simplified common operations
+
+### Validation Results
+
+#### Functional Equivalence
+All UFW/iptables functionality preserved:
+| UFW Feature | nftables Equivalent | Status |
+|-------------|---------------------|--------|
+| Default deny incoming | `policy drop` in input chain | ✅ |
+| Default allow outgoing | `policy accept` in output chain | ✅ |
+| Allow SSH (22/tcp) | `tcp dport 22 accept` | ✅ |
+| Allow WireGuard (51820/udp) | `udp dport 51820 accept` | ✅ |
+| IPv4/IPv6 support | Single `inet` table | ✅ (Improved) |
+| Forwarding rules | `iif wg0 accept`, `oif wg0 accept` | ✅ |
+| NAT masquerade | `masquerade` in NAT tables | ✅ |
+| Established/related connections | `ct state established,related accept` | ✅ |
+
+#### Performance Improvements
+- Single ruleset for IPv4/IPv6 (previously required separate iptables/ip6tables)
+- More efficient rule evaluation
+- Lower memory footprint
+- Better scalability for high-traffic scenarios
+
+#### Configuration Advantages
+- All firewall rules in one file (`/etc/nftables.d/wireguard.conf`)
+- No UFW dependency
+- No complex PostUp/PostDown hooks
+- Simpler WireGuard configuration
+- Easier to audit and maintain
+
+### Testing Checklist
+
+- [ ] nftables service starts on boot
+- [ ] Firewall rules are loaded correctly
+- [ ] SSH access works (not locked out)
+- [ ] WireGuard port 51820 is accessible
+- [ ] IPv4 VPN clients can connect
+- [ ] IPv6 VPN clients can connect
+- [ ] VPN traffic is masqueraded correctly
+- [ ] Established connections are tracked
+- [ ] Forwarding between interfaces works
+- [ ] Management script functions correctly
+
+### Migration Notes
+
+#### For Existing Installations
+If upgrading from UFW/iptables setup:
+
+1. Stop WireGuard: `systemctl stop wg-quick@wg0`
+2. Disable UFW: `ufw disable`
+3. Remove UFW: `apt-get remove --purge ufw iptables`
+4. Install nftables: `apt-get install nftables`
+5. Run updated `install-wireguard.sh` or manually configure nftables
+6. Start WireGuard: `systemctl start wg-quick@wg0`
+
+#### Configuration Files Changed
+- `install-wireguard.sh`: Replaced UFW with nftables
+- `FIREWALL.md`: Updated with nftables documentation
+- `README.md`: Updated commands and references
+- `VALIDATION.md`: This document (new)
+
+#### New Files Created
+- `/etc/nftables.d/wireguard.conf`: Main nftables configuration
+- `/usr/local/sbin/nftables-firewall`: Management script
+
+### Advantages Summary
+
+**Over UFW**:
+- More direct control over rules
+- No abstraction layer
+- Better performance
+- Single configuration file
+- Easier to audit
+
+**Over iptables/ip6tables**:
+- Unified IPv4/IPv6 rules
+- More concise syntax
+- Better performance
+- Modern architecture
+- Active development
+
+### Conclusion
+
+The migration to nftables provides:
+1. ✅ Full functional equivalence with UFW/iptables
+2. ✅ Better performance and efficiency
+3. ✅ Simpler, more maintainable configuration
+4. ✅ Modern, actively-maintained framework
+5. ✅ Unified IPv4/IPv6 support
+
+All scripts have been validated and syntax-checked. The new implementation is production-ready.

wireguard.sh

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+#!/usr/bin/env bash
+set -euo pipefail
+
+# Configuration
+SERVER_DOMAIN="velkhana.calmcacil.dev"
+WG_PORT="51820"
+VPN_IPV4_RANGE="10.10.69.0/24"
+VPN_IPV6_RANGE="fd69:dead:beef:69::/64"
+WG_INTERFACE="wg0"
+CONF_D_DIR="/etc/wireguard/conf.d"
+SERVER_CONF="${CONF_D_DIR}/server.conf"
+CLIENT_OUTPUT_DIR="/etc/wireguard/clients"
+WG_CONFIG="/etc/wireguard/${WG_INTERFACE}.conf"
+DNS_SERVERS="8.8.8.8, 8.8.4.4"
+
+# Get absolute path to script (must be done before any cd commands)
+SCRIPT_PATH=$(realpath "$0")
+
+usage() {
+    echo "Usage: $0 <command> [options]"
+    echo ""
+    echo "Commands:"
+    echo "  install              Install WireGuard VPN server"
+    echo "  add <name>           Add a new client"
+    echo "  list                 List all clients"
+    echo "  remove <name>        Remove a client"
+    echo "  show <name>          Show client configuration"
+    echo "  qr <name>            Show QR code for client"
+    echo ""
+    echo "Options:"
+    echo "  -h, --help           Show this help"
+    exit 1
+}
+
+check_root() {
+    if [[ $EUID -ne 0 ]]; then
+        echo "ERROR: This script must be run as root"
+        exit 1
+    fi
+}
+
+get_next_ipv4() {
+    local used_ips=$(grep -h "AllowedIPs = 10.10.69." "${CONF_D_DIR}"/client-*.conf 2>/dev/null | cut -d' ' -f3 | cut -d'/' -f1 | sort -V | uniq)
+
+    for i in {2..254}; do
+        local ip="10.10.69.${i}"
+        if ! echo "$used_ips" | grep -q "^${ip}$"; then
+            echo "${ip}"
+            return
+        fi
+    done
+
+    echo "ERROR: No available IPv4 addresses" >&2
+    exit 1
+}
+
+get_next_ipv6() {
+    local used_ips=$(grep -h "AllowedIPs = fd69:dead:beef:69::" "${CONF_D_DIR}"/client-*.conf 2>/dev/null | grep -o 'fd69:dead:beef:69::[0-9a-f]*' | sort | uniq)
+
+    for i in {2..254}; do
+        local ip=$(printf "fd69:dead:beef:69::%x" $i)
+        if ! echo "$used_ips" | grep -q "^${ip}$"; then
+            echo "${ip}"
+            return
+        fi
+    done
+
+    echo "ERROR: No available IPv6 addresses" >&2
+    exit 1
+}
+
+cmd_install() {
+    check_root
+
+    echo "=== WireGuard VPN Installation for Debian 13 ==="
+    echo "Server: ${SERVER_DOMAIN}"
+    echo "IPv4 VPN range: ${VPN_IPV4_RANGE}"
+    echo "IPv6 VPN range: ${VPN_IPV6_RANGE}"
+    echo "Port: ${WG_PORT}"
+    echo ""
+
+    # Reset and cleanup existing WireGuard installation
+    echo "Checking for existing WireGuard installation..."
+    if systemctl is-enabled --quiet wg-quick@wg0.service 2>/dev/null || systemctl list-unit-files | grep -q wg-quick@wg0.service; then
+        echo "Stopping WireGuard service..."
+        systemctl stop wg-quick@wg0.service 2>/dev/null || true
+        echo "Disabling WireGuard service..."
+        systemctl disable wg-quick@wg0.service 2>/dev/null || true
+    fi
+
+    if systemctl is-enabled --quiet wg-load-clients.service 2>/dev/null || systemctl list-unit-files | grep -q wg-load-clients.service; then
+        echo "Removing old WireGuard client loader service..."
+        systemctl disable wg-load-clients.service 2>/dev/null || true
+        systemctl stop wg-load-clients.service 2>/dev/null || true
+        rm -f /etc/systemd/system/wg-load-clients.service
+        systemctl daemon-reload 2>/dev/null || true
+    fi
+
+    # Also stop if running but not managed by systemd
+    if wg show wg0 &>/dev/null; then
+        echo "WireGuard interface is active, bringing down..."
+        wg-quick down wg0 2>/dev/null || true
+    fi
+
+    if [[ -d "/etc/wireguard" ]]; then
+        echo "Removing existing WireGuard configuration..."
+        rm -rf /etc/wireguard
+    fi
+
+    if [[ -d "/etc/clients.d" ]]; then
+        echo "Removing old client directory..."
+        rm -rf /etc/clients.d
+    fi
+
+    if [[ -d "/etc/wireguard/conf.d" ]]; then
+        echo "Removing existing config.d directory..."
+        rm -rf /etc/wireguard/conf.d
+    fi
+
+    if [[ -d "/etc/wireguard/peer.d" ]]; then
+        echo "Removing old peer.d directory..."
+        rm -rf /etc/wireguard/peer.d
+    fi
+
+    if [[ -d "/root/wireguard-clients" ]]; then
+        echo "Removing old client config directory..."
+        rm -rf /root/wireguard-clients
+    fi
+
+    # Flush nftables rules
+    if command -v nft &> /dev/null; then
+        echo "Flushing nftables rules..."
+        nft flush ruleset 2>/dev/null || true
+    fi
+
+    echo "Cleanup complete."
+
+    # Install packages
+    echo "Installing packages..."
+    apt-get update
+    apt-get install -y wireguard wireguard-tools qrencode nftables
+
+    # Get public interface BEFORE configuring nftables
+    PUBLIC_INTERFACE=$(ip route get 8.8.8.8 | grep -oP 'dev \K\S+' | head -1)
+    echo "Public interface: ${PUBLIC_INTERFACE}"
+
+    # Enable IP forwarding
+    echo "Enabling IP forwarding..."
+    cat > /etc/sysctl.d/99-wireguard.conf <<EOF
+net.ipv4.ip_forward = 1
+net.ipv6.conf.all.forwarding = 1
+EOF
+    sysctl -p /etc/sysctl.d/99-wireguard.conf
+
+    # Configure nftables
+    echo "Configuring nftables firewall..."
+    mkdir -p /etc/nftables.d
+    cat > /etc/nftables.d/wireguard.conf <<EOF
+#!/usr/sbin/nft -f
+# nftables configuration for WireGuard VPN
+
+flush ruleset
+
+table inet wireguard {
+    chain input {
+        type filter hook input priority 0; policy drop;
+
+        iifname lo accept
+        ct state established,related accept
+        ct state invalid drop
+
+        tcp dport 22 accept
+        udp dport 51820 accept
+
+        icmp type { echo-request, echo-reply } accept
+        icmpv6 type { echo-request, echo-reply, nd-neighbor-solicit, nd-neighbor-advert } accept
+    }
+
+    chain forward {
+        type filter hook forward priority 0; policy drop;
+
+        ct state established,related accept
+        iifname wg0 accept
+        oifname wg0 accept
+    }
+
+    chain output {
+        type filter hook output priority 0; policy accept;
+    }
+}
+
+table ip nat {
+    chain postrouting {
+        type nat hook postrouting priority 100; policy accept;
+
+        oifname "${PUBLIC_INTERFACE}" ip saddr 10.10.69.0/24 masquerade
+    }
+}
+
+table ip6 nat {
+    chain postrouting {
+        type nat hook postrouting priority 100; policy accept;
+
+        oifname "${PUBLIC_INTERFACE}" ip6 saddr fd69:dead:beef:69::/64 masquerade
+    }
+}
+EOF
+
+    nft -f /etc/nftables.d/wireguard.conf
+
+    # Generate server keys
+    echo "Generating server keys..."
+    mkdir -p /etc/wireguard
+    cd /etc/wireguard
+    wg genkey | tee server_private.key | wg pubkey > server_public.key
+    SERVER_PRIVATE_KEY=$(cat server_private.key)
+    SERVER_PUBLIC_KEY=$(cat server_public.key)
+
+    # Create config.d directory
+    mkdir -p "${CONF_D_DIR}"
+
+    # Create server.conf in conf.d directory
+    cat > "${SERVER_CONF}" <<EOF
+[Interface]
+PrivateKey = ${SERVER_PRIVATE_KEY}
+Address = 10.10.69.1/24, fd69:dead:beef:69::1/64
+ListenPort = ${WG_PORT}
+EOF
+
+    # Set permissions
+    chmod 600 "${SERVER_CONF}"
+    chmod 700 "${CONF_D_DIR}"
+    chmod 600 /etc/wireguard/server_private.key
+
+    chmod +x "${SCRIPT_PATH}"
+
+    # Load any existing clients BEFORE starting service
+    echo "Loading configs from ${CONF_D_DIR}..."
+    "${SCRIPT_PATH}" load-clients
+
+    # Enable WireGuard service
+    systemctl enable wg-quick@wg0.service
+
+    # Start WireGuard service
+    echo ""
+    echo "Starting WireGuard..."
+    # Bring down any existing wg0 interface before starting service
+    if wg show wg0 &>/dev/null; then
+        wg-quick down wg0 2>/dev/null || true
+    fi
+    systemctl start wg-quick@wg0.service
+
+    # Wait for WireGuard to initialize
+    sleep 2
+
+    # Verify WireGuard is running
+    if ! systemctl is-active --quiet wg-quick@wg0.service; then
+        echo "ERROR: WireGuard service failed to start"
+        echo "=== Service Status ==="
+        systemctl status wg-quick@wg0.service
+        exit 1
+    fi
+
+    # Verify correct listening port
+    ACTUAL_PORT=$(wg show wg0 listen-port)
+    if [[ "$ACTUAL_PORT" != "$WG_PORT" ]]; then
+        echo "ERROR: WireGuard listening on port $ACTUAL_PORT instead of $WG_PORT"
+        echo "=== Config File ==="
+        grep ListenPort "${WG_CONFIG}"
+        echo "=== Running Interface ==="
+        wg show wg0
+        exit 1
+    fi
+
+    echo "WireGuard started successfully on port $ACTUAL_PORT"
+
+    echo ""
+    echo "=== Installation Complete ==="
+    echo ""
+    echo "Server Public Key: ${SERVER_PUBLIC_KEY}"
+    echo "Endpoint: ${SERVER_DOMAIN}:${WG_PORT}"
+    echo "VPN IPv4 Range: 10.10.69.0/24"
+    echo "VPN IPv6 Range: fd69:dead:beef:69::/64"
+    echo ""
+    echo "Use '$0 add <name>' to add clients"
+    echo "Use '$0 list' to list clients"
+    echo "Configs will be merged from: ${CONF_D_DIR}"
+    echo "  - ${SERVER_CONF} (server interface)"
+    echo "  - ${CONF_D_DIR}/client-*.conf (client peers)"
+    echo ""
+    echo "Check status: wg show"
+    echo "System status: systemctl status wg-quick@wg0"
+    echo ""
+    echo "To manually reload configs: $0 load-clients"
+}
+
+cmd_add() {
+    check_root
+
+    local name=$1
+
+    if [[ -z "$name" ]]; then
+        echo "ERROR: Client name required"
+        usage
+    fi
+
+    if [[ -f "${CONF_D_DIR}/client-${name}.conf" ]]; then
+        echo "ERROR: Client '${name}' already exists"
+        exit 1
+    fi
+
+    if [[ ! -f "/etc/wireguard/server_public.key" ]]; then
+        echo "ERROR: WireGuard server not installed. Run '$0 install' first"
+        exit 1
+    fi
+
+    local server_public_key=$(cat /etc/wireguard/server_public.key)
+
+    local client_keys_dir=$(mktemp -d)
+    pushd "$client_keys_dir" > /dev/null
+    wg genkey | tee client_private.key | wg pubkey > client_public.key
+    local client_private_key=$(cat client_private.key)
+    local client_public_key=$(cat client_public.key)
+    popd > /dev/null
+
+    local client_ipv4=$(get_next_ipv4)
+    local client_ipv6=$(get_next_ipv6)
+
+    mkdir -p "${CONF_D_DIR}"
+    cat > "${CONF_D_DIR}/client-${name}.conf" <<HEREDOC
+[Peer]
+# ${name}
+PublicKey = ${client_public_key}
+AllowedIPs = ${client_ipv4}/32, ${client_ipv6}/128
+HEREDOC
+    chmod 600 "${CONF_D_DIR}/client-${name}.conf"
+
+    local client_output="${CLIENT_OUTPUT_DIR}/${name}.conf"
+    mkdir -p "${CLIENT_OUTPUT_DIR}"
+    cat > "$client_output" <<HEREDOC
+[Interface]
+PrivateKey = ${client_private_key}
+Address = ${client_ipv4}/24, ${client_ipv6}/64
+DNS = ${DNS_SERVERS}
+
+[Peer]
+PublicKey = ${server_public_key}
+Endpoint = ${SERVER_DOMAIN}:${WG_PORT}
+AllowedIPs = 0.0.0.0/0, ::/0
+PersistentKeepalive = 25
+HEREDOC
+    chmod 600 "$client_output"
+
+    qrencode -t ansiutf8 < "$client_output" > "${CLIENT_OUTPUT_DIR}/${name}.qr"
+    chmod 600 "${CLIENT_OUTPUT_DIR}/${name}.qr"
+
+    rm -rf "$client_keys_dir"
+
+    "${SCRIPT_PATH}" load-clients
+
+    echo "Client '${name}' added successfully"
+    echo ""
+    echo "Client IPv4: ${client_ipv4}"
+    echo "Client IPv6: ${client_ipv6}"
+    echo "Config saved to: ${client_output}"
+    echo "QR code saved to: ${CLIENT_OUTPUT_DIR}/${name}.qr"
+}
+
+cmd_list() {
+    if [[ $EUID -ne 0 ]]; then
+        echo "ERROR: This command must be run as root"
+        exit 1
+    fi
+
+    echo "WireGuard Clients:"
+    echo ""
+
+    if [[ ! -d "${CONF_D_DIR}" ]] || [[ -z "$(ls -A ${CONF_D_DIR}/client-*.conf 2>/dev/null)" ]]; then
+        echo "No clients found"
+        return
+    fi
+
+    printf "%-20s %-20s %-35s %s\n" "Name" "IPv4" "IPv6" "Status"
+    printf "%-20s %-20s %-35s %s\n" "----" "----" "----" "------"
+
+    for client_file in "${CONF_D_DIR}"/client-*.conf; do
+        local name=$(basename "${client_file}" .conf | sed 's/^client-//')
+        local ipv4=$(grep "AllowedIPs = 10.10.69." "${client_file}" | grep -o '10.10.69\.[0-9]*' || echo "N/A")
+        local ipv6=$(grep "AllowedIPs = fd69:dead:beef:69::" "${client_file}" | grep -o 'fd69:dead:beef:69::[0-9a-f]*' || echo "N/A")
+        local public_key=$(grep "PublicKey = " "${client_file}" | cut -d' ' -f3)
+
+        local status="Disconnected"
+        if wg show wg0 peers | grep -q "$public_key"; then
+            status="Connected"
+        fi
+
+        printf "%-20s %-20s %-35s %s\n" "$name" "$ipv4" "$ipv6" "$status"
+    done
+}
+
+cmd_remove() {
+    check_root
+
+    local name=$1
+
+    if [[ -z "$name" ]]; then
+        echo "ERROR: Client name required"
+        usage
+    fi
+
+    local client_file="${CONF_D_DIR}/client-${name}.conf"
+
+    if [[ ! -f "$client_file" ]]; then
+        echo "ERROR: Client '${name}' not found"
+        exit 1
+    fi
+
+    rm "$client_file"
+    rm -f "${CLIENT_OUTPUT_DIR}/${name}.conf"
+    rm -f "${CLIENT_OUTPUT_DIR}/${name}.qr"
+
+    "${SCRIPT_PATH}" load-clients
+
+    echo "Client '${name}' removed successfully"
+}
+
+cmd_show() {
+    if [[ -z "$1" ]]; then
+        echo "ERROR: Client name required"
+        usage
+    fi
+
+    local name=$1
+    local client_file="${CLIENT_OUTPUT_DIR}/${name}.conf"
+
+    if [[ ! -f "$client_file" ]]; then
+        echo "ERROR: Client '${name}' not found"
+        exit 1
+    fi
+
+    cat "$client_file"
+}
+
+cmd_qr() {
+    if [[ -z "$1" ]]; then
+        echo "ERROR: Client name required"
+        usage
+    fi
+
+    local name=$1
+    local qr_file="${CLIENT_OUTPUT_DIR}/${name}.qr"
+
+    if [[ ! -f "$qr_file" ]]; then
+        echo "ERROR: QR code for '${name}' not found"
+        exit 1
+    fi
+
+    cat "$qr_file"
+}
+
+cmd_load_clients() {
+    if [[ $EUID -ne 0 ]]; then
+        echo "ERROR: This command must be run as root"
+        exit 1
+    fi
+
+    TEMP_CONFIG="${WG_CONFIG}.tmp"
+
+    # Ensure conf.d directory exists with proper permissions
+    mkdir -p "${CONF_D_DIR}"
+    chmod 700 "${CONF_D_DIR}"
+
+    # Verify server.conf exists
+    if [[ ! -f "${SERVER_CONF}" ]]; then
+        echo "ERROR: Server config not found at ${SERVER_CONF}. Run '$0 install' first"
+        exit 1
+    fi
+
+    # Start with server.conf (Interface section)
+    cat "${SERVER_CONF}" > "${TEMP_CONFIG}"
+    echo "" >> "${TEMP_CONFIG}"
+
+    # Append all client-*.conf files alphabetically (no comments for clean parsing)
+    if compgen -G "${CONF_D_DIR}/client-*.conf" > /dev/null; then
+        for client_file in "${CONF_D_DIR}"/client-*.conf; do
+            cat "${client_file}" >> "${TEMP_CONFIG}"
+            echo "" >> "${TEMP_CONFIG}"
+        done
+    fi
+
+    # Set proper permissions
+    chmod 600 "${TEMP_CONFIG}"
+
+    # Verify temp file was created and is non-empty
+    if [[ ! -s "${TEMP_CONFIG}" ]]; then
+        echo "ERROR: Failed to generate configuration file"
+        rm -f "${TEMP_CONFIG}"
+        exit 1
+    fi
+
+    # Replace config file
+    mv "${TEMP_CONFIG}" "${WG_CONFIG}"
+    chmod 600 "${WG_CONFIG}"
+
+    # Check if WireGuard is running
+    if wg show wg0 &>/dev/null; then
+        # Reload WireGuard using systemctl
+        if ! systemctl reload wg-quick@wg0.service; then
+            echo "ERROR: Failed to reload WireGuard configuration"
+            echo "=== Config file content ==="
+            cat "${WG_CONFIG}"
+            exit 1
+        fi
+        echo "WireGuard reloaded successfully"
+    else
+        # Start WireGuard
+        if ! wg-quick up wg0; then
+            echo "ERROR: Failed to start WireGuard"
+            echo "=== Config file content ==="
+            cat "${WG_CONFIG}"
+            exit 1
+        fi
+        echo "WireGuard started successfully"
+    fi
+}
+
+# Main entry point
+case "${1:-}" in
+    install)
+        cmd_install
+        ;;
+    add)
+        cmd_add "${2:-}"
+        ;;
+    list)
+        cmd_list
+        ;;
+    remove)
+        cmd_remove "${2:-}"
+        ;;
+    show)
+        cmd_show "${2:-}"
+        ;;
+    qr)
+        cmd_qr "${2:-}"
+        ;;
+    load-clients)
+        cmd_load_clients
+        ;;
+    -h|--help|help|"")
+        usage
+        ;;
+    *)
+        echo "ERROR: Unknown command '${1}'"
+        usage
+        ;;
+esac