Offline networking: Difference between revisions

Due to our habitual relationship with WiFi and connecting to the public Internet, we can often overlook WiFi's applications in 'offline' contexts. A a WiFi access point (AP) does not need the public Internet to provide access to content, if the content is locally accessible to the AP. In such applications, either the WiFi router itself holds the data (perhaps on a USB stick), or the data is served from another device connected directly to the AP. This is an interesting direction for those more technically minded wishing to provide a source of information (like a WiKi or message board) when the Internet is down. Due to the short range of WiFi, such offline access point servers are best setup at a common communal area, like a community center or disaster meeting point.

Some commercial routers provide ability for file sharing across their network using the factory firmware installed on the device. However in the majority of applications, an ''after market'' firmware is used, like OpenWrt<ref>https://openwrt.org</ref>. For those more technically inclined, OpenWrt is an open source project and community dedicated to writing and testing firmware that can be 'flashed' onto scavenged or bought WiFi routers, providing them with new functionality and customisation options. At the time of writing, 2043 wireless routers are supported by OpenWrt to some degree<ref>https://openwrt.org/toh/start</ref>.

Many projects have been done exploring the practical application of offline networking in a wireless context using OpenWrt. However, many small form-factor computers can be repurposed as WiFi access points, that either route through to another network (like the Internet) or remain hermetic.  

==== Turning an old laptop into an offline wireless server ====

Any GNU/Linux laptop or device with a wireless network adapter can be repurposed as a wireless access point serving information and files from a locally hosted website. A popular webserver for use in such contexts is ''lighttpd''. A popular daemon/service providing access point functionality is ''hostapd'', often coupled with ''dnsmasq'' to provide automatic network configuration of clients using the DHCP protocol alongside domain name resolution<ref>https://w1.fi/hostapd/</ref><ref>https://dnsmasq.org/</ref>.

The Meshtastic project is a unique LoRa implementation with a very large global community of user-operated mesh nodes. This consumer-facing solution provides a modular platform whereby LoRa hardware, battery, and case and antenna are purchased, a web-based flasher is used to deploy the software onto the hardware. Various interfaces to the hardware (including apps and web-based) are provided. Meshtastic can be a good solution for resilient communications, especially for those less technical. Setup and configuration is done on a smartphone via an app, and requires little-to-no prior knowledge. A large community exists to support those less technical.  

Meshtastic leverages the fact that people are often already carrying smartphones, allowing messages to be sent from a paired smartphone over bluetooth to the device, the messages of which are in turn either broadcast to a public channel on the mesh, or to a user-configured encrypted channel of devices on the mesh (for instance to devices of friends and family in the region).<ref>https://meshtastic.org/</ref>. In this sense, Meshtastic can be considered to be a little like a long range 'pager' using a smartphone as the messaging interface.