Setting up Kali as a Router/Wireless Access Point

Below is a bash script I created to set up Kali as a Router/Wireless Access Point. Please note:
1. If you are using a VM, set your network adapter to bridged adapter. Then choose your internal wireless card (if using wifi) or your modem (if using ethernet).
2. Ensure you have a wireless interface adapter (such as wlan0) enabled, before running the script and after your machine restarts.
3. If your router is on the 192.168.10.0/24 subnet (not likely), you will need to change the ip addresses in the script so it is outside the subnet used by your router.
4. Create the script file in Linux. If you create it in Windows and move it to your Linux environment, you will need to run this command to convert the script to use Unix-style line endings: dos2unix your_script_name.sh
5. Before running the script, you will need to run this command to make the script executable: chmod +x your_script_name.sh
6. You need to run the script with sudo for it to execute successfully and without user interaction: sudo ./your_script_name.sh

Enjoy!

SCRIPT BELOW:

#!/bin/bash
# Prompt for SSID and Passphrase
read -p "Enter SSID: " ssid
read -p "Enter Passphrase: " passphrase
read -p "Wireless Interface: " interface


#Step 1: Set up wireless interface and set subnet.
sudo ip addr add 192.168.10.1/24 dev $interface
sudo ip link set "$interface" up


# Step 2: Configure Network Interface
echo "Configuring network interface..."
cat <<EOF > /etc/network/interfaces
source-directory /etc/network/interfaces.d
auto lo
iface lo inet loopback
allow-hotplug wlan0
iface wlan0 inet static
address 192.168.10.1
netmask 255.255.255.0
EOF
systemctl enable networking


# Step 3: Create WAP Configuration
sudo apt install -y hostapd
echo "Creating hostapd configuration..."
sudo bash -c "cat > /etc/hostapd/hostapd.conf <<EOF
interface=$interface
driver=nl80211
ssid=$ssid
hw_mode=g
channel=7
wmm_enabled=0
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_passphrase=$passphrase
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP
EOF"
sudo systemctl unmask hostapd
sudo systemctl enable hostapd


# Step 4: Configure DNS and DHCP
echo "Configuring dnsmasq..."
cat <<EOF > /etc/dnsmasq.conf
interface=$interface
dhcp-range=192.168.10.50,192.168.10.150,12h
dhcp-option=3,192.168.10.1
dhcp-option=6,8.8.8.8,8.8.4.4
EOF
apt install dnsmasq
systemctl enable dnsmasq


# Step 5: Enable IPv4 Forwarding
echo "Enabling IPv4 forwarding..."
echo "net.ipv4.ip_forward=1" > /etc/sysctl.conf


# Step 6: Set NAT and Firewall Rules
echo "Setting up iptables rules..."
mkdir -p /etc/iptables
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
iptables -A FORWARD -i eth0 -o $interface -m state --state RELATED,ESTABLISHED -j ACCEPT
iptables -A FORWARD -i $interface -o eth0 -j ACCEPT
iptables-save > /etc/iptables/rules.v4


# Set DEBIAN_FRONTEND to noninteractive to auto-accept prompts
export DEBIAN_FRONTEND=noninteractive


# Install iptables-persistent without manual confirmation
apt-get install -y iptables-persistent


# Reset DEBIAN_FRONTEND to its default value
unset DEBIAN_FRONTEND


# Step 7: Enable netfilter-persistent and Reboot
echo "Enabling netfilter-persistent..."
systemctl enable netfilter-persistent


reboot