Setting Up a WiFi Hotspot on Linux: A Step-by-Step Guide

Creating a WiFi hotspot on Linux transforms your computer into a wireless access point, perfect for sharing internet or creating a local network. Here’s how to do it using hostapd (Host Access Point Daemon) and dnsmasq (DHCP/DNS server).

Prerequisites

1. Wireless Adapter: Must support “AP mode” (check with iw list | grep "AP").
2. Admin Access: Run all commands with sudo.
3. Internet Connection: For sharing via Ethernet (e.g., eth0) or another interface.

Step 1: Install Tools

Open a terminal and install:

sudo apt update && sudo apt install hostapd dnsmasq  

Step 2: Configure HostAPD (Access Point)

1. Create a config file:

   sudo nano /etc/hostapd/hostapd.conf  

2. Paste this (adjust ssid, wpa_passphrase, and channel):

   interface=wlan0  
   driver=nl80211  
   ssid=MyLinuxHotspot  
   hw_mode=g  
   channel=6  
   wmm_enabled=0  
   macaddr_acl=0  
   auth_algs=1  
   ignore_broadcast_ssid=0  
   wpa=2  
   wpa_passphrase=SecurePassword123  
   wpa_key_mgmt=WPA-PSK  
   rsn_pairwise=CCMP  

   • Replace wlan0 with your wireless interface (find via iw dev).

Step 3: Configure DNSMasq (DHCP Server)

1. Backup the default config:

   sudo mv /etc/dnsmasq.conf /etc/dnsmasq.conf.backup  

2. Create a new config:

   sudo nano /etc/dnsmasq.conf  

3. Paste:

   interface=wlan0  
   dhcp-range=192.168.100.2,192.168.100.254,255.255.255.0,24h  
   dhcp-option=3,192.168.100.1  
   server=8.8.8.8  

   • This assigns IPs between 192.168.100.2–192.168.100.254.

Step 4: Set Up Routing & NAT

1. Assign IP to wlan0:

   sudo ip addr add 192.168.100.1/24 dev wlan0  

2. Enable IP forwarding:

   sudo sysctl net.ipv4.ip_forward=1  

3. Configure NAT (replace eth0 with your internet source):

   sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE  
   sudo iptables -A FORWARD -i wlan0 -o eth0 -j ACCEPT  

Step 5: Start the Hotspot

1. Stop conflicting services:

   sudo systemctl stop systemd-networkd wpa_supplicant  

2. Start hostapd and dnsmasq:

   sudo systemctl start hostapd dnsmasq  

3. (Optional) Enable auto-start on boot:

   sudo systemctl enable hostapd dnsmasq  

Step 6: Connect Devices

Scan for WiFi networks on your phone/laptop and connect to:

• SSID: MyLinuxHotspot
• Password: SecurePassword123

Stopping the Hotspot

sudo systemctl stop hostapd dnsmasq  
sudo sysctl net.ipv4.ip_forward=0  
sudo iptables -t nat -D POSTROUTING -o eth0 -j MASQUERADE  # Remove NAT rule  

Troubleshooting

• No Internet? Verify NAT rules (sudo iptables -t nat -L) and internet source interface.
• AP Not Visible? Check hostapd logs: journalctl -u hostapd.
• Conflict with Network Manager? Disable it:

  sudo systemctl stop NetworkManager  

Conclusion

You’ve created a secure WiFi hotspot on Linux! This setup works on Ubuntu/Debian. For Fedora/Arch, use firewalld instead of iptables. Customize the SSID, password, and IP range as needed. Share your experience in the comments!