I use chat mail relay, I really like everything. I set it up and started distributing it to friends, family, colleagues, they all successfully logged in, we communicated and everything is fine. Soon I decided to change the hosting provider, I destroyed the server, transferred the domain name to a new hosting, created a server there, installed chat mail relay from scratch but under the same domain name, and then an interesting thing happened, everyone who was registered on the previous server, somehow the Delta Chat client was able to reconnect and continue working on a new server without re-authorization.
I wanted to know:
How is this possible?
How should I move the server without losing users?
Is there a command to backup the entire chat mail relay with users, for transportation to another server?
Chatmail addresses are automatically created at first login
When you created a new server, there were no users registered on it. When the users of the old server tried to log in, this automatically created their accounts.
Chatmail servers are not very stateful. This is partially why some people would like to rename them to “Chatmail relays”, which is also evident on https://chatmail.at/.
However, the fact that this worked doesn’t mean that this is how one should transfer a Chatmail server to another machine. What could have happened is that a malicious actor could spam the server with login attempts with known account email addresses from the previous machine, but with random passwords, which could have locked out previous users from their accounts.
Additionally, some yet to be delivered emails could have been lost.