Wow. Sounds interesting. I also looked for a solution to talk to relatives in case the internet gets blocked. Ended up with XMPP, since it has independent servers in different countries that can talk to each other. But the XMPP clients I tried are pretty bad, with no images or audio/video calls.
Did video calls work during the blackout too? I think calls should work like in the good old Skype days, pure P2P.
Yes, the chatmail servers (https://chatmail.at) come with a coturn server that keeps the video calls P2P if possible.
I am going to bite - how would servers work in other country if you have internet blocked, what am i missing here?
Not the person you are asking but countries rarely block the internet for real. War torn countries will immediately block full MTU packets (bulk traffic packets, this will block streaming services), known social media platforms, known chat services. It will appear down. Cloudflare stats will give the appearance of being down but small unknown chat platforms may work for a little while. SSH may work even longer as they need SSH and even telnet to continue to manage infrastructure. That's why I keep an SSH chat server around. Feel free to play around with it. [1] When sharing with a person in a war torn country, give them the IP not the domain name. There will also be networks that allow leaders to bypass the "blocks".
[1] (customize username, paste into terminal, then type "chat") .:. This is a hardened private fork of devzat. shout-out to quackduck if he still logs in here.
Useful commands to start with are "help", "cmds" and "rest". There is no censorship.Adding on to Bender's post, most of the blocking I've seen happens at consumer oriented ISPs. Sometimes the regulator only asks mobile carriers, so residential wired internet still works fine. Sometimes they'll get residential and mobile, but not offices. If there's in country servers/datacenters, those might not have filtering and also be reachable domestically.
It really depends a lot on what's going on that they want to block. Making it hard for people to do X is often good enough. For some things, making it unreliable is more effective than a complete block, because a complete block leads people towards circumvention but unreliability can push towards local alternatives instead.
This is one of the merits of federation, one that Signal doesn't have.
While the Internet is cut off in authoritarian regimes, the intranet (note the difference) rarely is. The regimes have to preserve the internal network in the country because otherwise financial infra like banking will be down too. So a VPS or a computer connected to a public IP inside the country is all you need.