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Setting up captive portal (Wifi) on raspi

Using nodogsplash.

First set up the raspi as a WiFi access point (AP)​

Following these installation instructions and referencing the official Pi directions.

Install the software packages:

sudo apt update
sudo apt -y upgrade
sudo apt install -y hostapd dnsmasq
sudo systemctl unmask hostapd
sudo systemctl enable hostapd
sudo DEBIAN_FRONTEND=noninteractive apt install -y netfilter-persistent iptables-persistent

and then rebooting

sudo reboot

Add the following code to the file /etc/dhcpcd.conf

cat <<EOF | sudo tee -a /etc/dhcpcd.conf

interface wlan0
    static ip_address=192.168.4.1/24
    nohook wpa_supplicant
EOF

and likewise for /etc/sysctl.d/routed-ap.conf

cat <<EOF | sudo tee -a /etc/sysctl.d/routed-ap.conf
# Enable IPv4 routing
net.ipv4.ip_forward=1
EOF

and same for /etc/dnsmasq.conf

cat <<EOF | sudo tee -a /etc/dnsmasq.conf
interface=wlan0 # Listening interface
dhcp-range=10.0.0.2,10.0.0.12,255.255.255.0,24h
                # Pool of IP addresses served via DHCP
domain=wlan     # Local wireless DNS domain
address=/gw.wlan/10.0.0.1
                # Alias for this router
EOF

and also for /etc/hostapd/hostapd.conf

cat <<EOF | sudo tee -a /etc/hostapd/hostapd.conf
country_code=AU
interface=wlan0
ssid=NoDoggySplashy
hw_mode=g
channel=11
#ssid=NoDoggySplashy5G
#hw_mode=a
#channel=48
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
#wpa=2
#wpa_passphrase=qwertyuiop
#wpa_key_mgmt=WPA-PSK
#wpa_pairwise=TKIP
#rsn_pairwise=CCMP
EOF
sudo raspi-config nonint do_wifi_country AU
sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
sudo netfilter-persistent save
sudo reboot

The AP should now be visible to other devices with WiFi enabled.

Captive portal nodogsplash​

For the nodogsplash installation, install requirements, obtain software and compile it as follows:

sudo apt-get update
sudo apt install git libmicrohttpd-dev build-essential git libmicrohttpd-dev build-essential -y
cd ~
git clone https://github.com/nodogsplash/nodogsplash.git
cd nodogsplash
make
sudo make install

Make sure the following settings are correct in /etc/nodogsplash/nodogsplash.conf

GatewayInterface wlan0
GatewayAddress 192.168.1.237

Set the the captive portal to start automagically and start it now:

sudo cp ~/nodogsplash/debian/nodogsplash.service /lib/systemd/system/
sudo systemctl enable nodogsplash.service 
sudo systemctl start nodogsplash.service

And checking the status

sudo systemctl status nodogsplash.service

should show something like

● nodogsplash.service - NoDogSplash Captive Portal
   Loaded: loaded (/lib/systemd/system/nodogsplash.service; enabled; vendor preset: enabled)
   Active: active (running) since Tue 2023-03-14 04:27:45 GMT; 12min ago
  Process: 673 ExecStart=/usr/bin/nodogsplash $OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 678 (nodogsplash)
    Tasks: 4 (limit: 2059)
   CGroup: /system.slice/nodogsplash.service
           └─678 /usr/bin/nodogsplash

Mar 14 04:27:44 raspi303 systemd[1]: Starting NoDogSplash Captive Portal...
Mar 14 04:27:45 raspi303 nodogsplash[673]: [5][Tue Mar 14 04:27:45 2023][673](src/main.c:359) Starting as daemon, forking to background
Mar 14 04:27:45 raspi303 nodogsplash[673]: [5][Tue Mar 14 04:27:45 2023][678](src/main.c:273) Detected gateway wlan0 at 192.168.1.237 (b8:27:eb:a6:b5:f1)
Mar 14 04:27:45 raspi303 nodogsplash[673]: [5][Tue Mar 14 04:27:45 2023][678](src/main.c:289) Created web server on 192.168.1.237:2050
Mar 14 04:27:45 raspi303 systemd[1]: Started NoDogSplash Captive Portal.
Mar 14 04:27:45 raspi303 nodogsplash[673]: [5][Tue Mar 14 04:27:45 2023][678](src/fw_iptables.c:380) Initializing firewall rules
Mar 14 04:28:31 raspi303 nodogsplash[673]: [5][Tue Mar 14 04:28:31 2023][678](src/client_list.c:139) Adding 10.0.0.3 52:1d:b8:2e:05:de token 7ef0af99 to client list
Mar 14 04:38:47 raspi303 nodogsplash[673]: [5][Tue Mar 14 04:38:47 2023][678](src/auth.c:188) Timeout preauthenticated idle user: 10.0.0.3 52:1d:b8:2e:05:de, inactive: 616s, in: 0kB, out: 0kB
Mar 14 04:38:47 raspi303 nodogsplash[673]: [5][Tue Mar 14 04:38:47 2023][678](src/client_list.c:370) Deleting 10.0.0.3 52:1d:b8:2e:05:de token 7ef0af99 from client list

Accessing the AP shows the following

bada30367ab3bda708bbc8625c1644a2.png