Offgrid Raspberry Pi Setup

I find that the easiest way to setup your Pi on the first boot up is to connect it to a monitor, keyboard, mouse and wired ethernet. There are advanced options for connecting directly to your Pi over a network on the initial boot up, but that is beyond the scope of this document.

Once you have everything connected, turn on your Pi. You should be greeted with a welcome dialog. Perform the following:

1. Set country and language.
2. Set a password.
3. Skip the WiFi network screen. We will be performing an advanced network configuration later.
4. Skip the software update. We will do this manually.
5. When asked to reboot, select Later.

Next, open a terminal window. We will configure some initial network settings so that we can connect to this system remotely. This will be the last time that the Pi will be connected to a monitor, keyboard and mouse.

1. Configure the Pi.

   $ sudo raspi-config

2. Set the hostname: System Options > Hostname. I like to name the Pi after my radio (i.e. ft60r).

3. Set the screen resolution: Display Options > Resolution. I set the screen resolution to a size that is appropriate for a remote desktop connection. I find that 1280x700 works well when I connect to the desktop remotely from my iPad Mini.

4. Since we plan to connect to the Pi remotely, we will enable two network services on the Pi. Navigate to Interface Options and enable SSH and VNC.

5. Now, select Finish. Select No when asked to reboot.

6. Make a note of the IP address of your Pi's wired ethernet by executing:

$ ifconfig eth0 | grep inet

7. Shutdown the Pi.

$ sudo shutdown -h now

8. Disconnect the monitor, keyboard and mouse.

At this point, you should have two cables connected: the power and ethernet cables. Turn on your Pi.

As I mentioned earlier, I intend to use my Raspberry Pi in the field without access to the Internet. However, I still need the ability to connect to it remotely from my phone, tablet or laptop. To achieve this goal we will configure our Pi to act as a wireless access point.

In this section, we will configure our access point to use the 192.168.5.0/24 network and we'll name our WiFi access point after the radio we plan to use with it. Trust me, when you have three or four Pi's, this will help.

1. Ensure your Pi is still connected to your ethernet network as we need access to the internet for this section.

2. Remotely connect to the Pi from another computer using an SSH client. On Windows, you can download Putty. Under Mac or Linux, simply open a terminal and execute:

$ ssh pi@ip-address-of-your-pi

Remember: we made a note of the Pi's IP address in the last section.

3. Once logged in, update the OS.

$ sudo apt update
$ sudo apt upgrade

4. Install access point and DNS software.

$ sudo apt install hostapd dnsmasq -y

5. Enable access point software and enable on boot.

$ sudo systemctl unmask hostapd
$ sudo systemctl enable hostapd

6. Allow firewall rules to be preserved on reboot.

$ sudo DEBIAN_FRONTEND=noninteractive apt install -y netfilter-persistent iptables-persistent

7. Configure DHCP.

$ sudo nano /etc/dhcpcd.conf

Add the following to the end:

interface wlan0
    static ip_address=192.168.5.1/24
    nohook wpa_supplicant

8. Enable routing and IP masquerading.

$ sudo nano /etc/sysctl.d/routed-ap.conf

Add the following:

# Enable IPv4 routing
net.ipv4.ip_forward=1

9. Enable IP masquerading and save the firewall rules. Note: if the iptables command fails with "iptables/1.8.2 Failed to initialize nft: Protocol not supported", try to unplug the WiFi dongle, then re-run the command, then re-connect the WiFi dongle.

$ sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
$ sudo netfilter-persistent save

10. Configure DNS and DHCP for the wireless network.

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

Add the following to the end:

interface=wlan0 # Listening interface
dhcp-range=192.168.5.2,192.168.5.20,255.255.255.0,24h
        # Pool of IP addresses served via DHCP
domain=wlan     # Local wireless DNS domain
address=/gw.wlan/192.168.5.1
        # Alias for this router

11. Enable wireless operation.

$ sudo rfkill unblock wlan

12. Configure the access point. Change the SSID and password accordingly. I like to set the SSID to the name of my radio (which also happens to be the same as the hostname that we set earlier).

$ sudo nano /etc/hostapd/hostapd.conf

Add the following:

country_code=US
interface=wlan0
ssid=ft60r
hw_mode=g
channel=7
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_passphrase=hamradio
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP

13. Reboot.

$ sudo reboot

14. When the system reboots, it should start up as a wireless access point. Connect to its WiFi hotspot from another computer and test the connection.

15. Now, your Pi will always be available at a fixed IP address (192.168.5.1). Therefore, when you associate a device to this WiFi hotspot, you will be assigned an IP address on the 192.168.5.0/24 network. You can remotely connect via SSH (ssh pi@192.168.5.1) or via VNC.

This approach was based on this article.