RaspberryPi:AdvancedConnectivity

Overview

This page covers advanced connectivity options that you can use on the Raspberry Pi. While not always required, they can simplify and streamline the way you work with the Raspberry Pi.

For issues with connectivity, visit RaspberryPi:DebuggingConnectivity

Configuring the Pi to Act as an Access Point

If you are hosting a server on the Raspberry Pi, or perhaps want to create a WiFi network for guests to connect to, the Pi can act as an access point. This guide comes from https://www.raspberrypi.org/documentation/configuration/wireless/access-point.md and https://frillip.com/using-your-raspberry-pi-3-as-a-wifi-access-point-with-hostapd/ and will work with a Pi that has an Ethernet Port (though it it possible to mimic an Ethernet port on a Pi 0W over USB. A Pi 0 doesn't have WiFi so this wouldn't serve any purpose).

Note that this WiFi connection will not provide internet access by bridging the Ethernet port (that’s something else entirely), but it works well for hosting services on the Pi, such as a Node-Red server.

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1. SSH into the Pi, update, and reboot to ensure updates have taken place

   $ sudo apt-get update
   $ sudo apt-get dist-upgrade
   $ sudo reboot

2. Wait for the Pi to reboot, and reconnect via SSH. Install hostapd and dnsmasq

   $ sudo apt-get install hostapd dnsmasq

3. Configure a static IP in dhcpcd

   $ sudo nano /etc/dhcpcd.conf

   Adjust the contents so that the wireless interface is described as follows:

   interface wlan0
   static ip_address=192.168.4.1/24
   nohook wpa_supplicant

   Save and close that file, and restart the dhcp service

   $ sudo systemctl restart dhcpcd

4. Run the following commands to create save the original dnsmasq, and create a new file which will be edited:

   $ sudo mv /etc/dnsmasq.conf /etc/dnsmasq.conf.orig
   $ sudo nano /etc/dnsmasq.conf

   Place the following in the now open file:

   interface=wlan0
   listen-address=192.168.4.1
   dhcp-range=192.168.4.2,192.168.4.180,255.255.255.0,24h
   server=8.8.8.8
   domain-needed
   bogus-priv

   Save and close the file

5. Restart the dnsmasq service

   $ sudo systemctl reload dnsmasq

6. Configure hostapd. Open up the configuration file:

   sudo nano /etc/hostapd/hostapd.conf

   Place the following configuration in the file. Some assumptions are made about the technical aspects of it, but these are beyond the scope of this course. Note that network name and password do not have quotes around them.

   interface=wlan0
   driver=nl80211
   ssid=TestNetwork
   hw_mode=g
   channel=7
   ieee80211n=1
   wmm_enabled=1
   macaddr_acl=0
   auth_algs=1
   ignore_broadcast_ssid=0
   wpa=2
   wpa_passphrase=TestNetwork
   wpa_key_mgmt=WPA-PSK
   wpa_pairwise=TKIP
   rsn_pairwise=CCMP

   Save and close the file

7. Next, the system needs to know where to find this configuration file. Open the configuration file:

   $ sudo nano /etc/default/hostapd

   Find the line with “#DAEMON_CONF” and replace it with:

   DAEMON_CONF="/etc/hostapd/hostapd.conf"

   Save and close this file.

8. Now enable and start hostapd:

   $ sudo systemctl unmask hostapd
   $ sudo systemctl enable hostapd
   $ sudo systemctl start hostapd

9. Add routing and masquerade by opening sysctl:

   $ sudo nano /etc/sysctl.conf

   And uncomment this line by removing the preceding # symbol:

   net.ipv4.ip_forward=1

   Save and close the file

10. Add a masquerade, and save the iptables rule:

    $ sudo iptables -t nat -A  POSTROUTING -o eth0 -j MASQUERADE
    $ sudo sh -c "iptables-save > /etc/iptables.ipv4.nat"

11. Edit /etc/rc.local and add this just above “exit 0” to install these rules on boot.

    $ sudo nano /etc/rc.local

    Place the following just above “exit 0” to install these rules on boot

    iptables-restore < /etc/iptables.ipv4.nat