My personal server only served a few real users to this day, which means that each of us had an account on the server, that owned files and could run commands, schedule tasks, and so on.
I just extended my hosting perimeter, but I only allow email usage for my new guests so far. With this in mind, I did not want to create new Linux accounts, which would have needlessly weakened my server by exposing it to attacks towards these new accounts. Thus I created my first virtual users, for electronic mail.
I found several configuration examples on the Internet, but those mostly addressed situations where all users were virtual, often in several domains, or where a given domain was targeted at real users while others domains were targeted at virtual users. My wish was rather to allow new, virtual, users into my existing domains, the users of which were so far of the real kind only. Still, by taking from all those readings, it was not that hard to get there.
Cet article existe aussi en français.