Hi!

I live in seismic active zone and would like to elaborate a basic draft for Emergency WiFi network implementation.

Intro.
During latest seismic events all mobile networks were disabled, an access to fixed line phone was limited as we were instructed to leave buildings and stay at open air areas for about 2-4 hours. Apparently the Internet was working all the time.

Plan.
I am thinking about Emergency WiFi Network.

Its first stage should include ordinary WiFi router with walled garden and captive portal connected to my Internet connection.

Walled garden will provide access to WhatsApp and Telegram servers only for minimal messaging functionality. Additional services might be opened later depending on demand.

Captive portal should provide at least one page with basic information about this service and current emergency situation.

Its second stage should include high power outdoor equipment connected to same private Internet connection but located at roof for bigger coverage area.

Its third stage should include support for mesh networking with just one device connected to Internet.

Its fourth stage should include support for shared multiple Internet connections support.

A solution for messaging similar to WhatsApp and Telegram in this private network would be a plus.

The questions I have right now are:
0. Do you know about any project with similar functionality?
1. Which soft to use to implement walled garden? Just iptables?
2. Which soft to use to implement minimal captive portal? I need just one web page.
3. Any recommendations for AP high power hardware? Ubiquiti UniFi AC Mesh? Wavlink AC600 Outdoor Wi-Fi High Power Range Extender WL-WN570HA1?
4. Any recommendations for mesh network implementation?
5. Any recommendations for software for private network messaging?
6. Any general recommendations about this network implementation?

Thank you in advance for  your kind attention to my project.

While configuring a captive portal isn't difficult, actually restricting the allowed services to messengers only is. The service providers are rather unlikely to publish the required information, and trying to reverse engineer their IPs would be very high maintenance (most traffic will be SSL/ TLS encrypted as well) - pretty much guaranteed to fail in the actual emergency case.

Your best option would probably be to only enable the service in case of emergencies and to throttle the throughpout so much that it's simply not attractive (downright painful) for interactive uses.

Thank you for sharing your thoughts, you are so right - it would be impossible to whitelist messaging providers. Maybe I will blacklist popular social networks. Your suggestion to throttle the throughput is just great.