Local and remote users
At the highest level, there are two basic ways to think of user accounts on any system. The first is local accounts that exist on the local system where they are being used. The second is user accounts stored remotely on some sort of server that the local system references over the network. Of course, there are hybrid methods that combine these techniques in various ways as well.
We should start by talking about the obvious benefits to both approaches. With locally managed user accounts we have lightning-fast access to our account information and no dependence on the network. This provides obvious performance advantages, better security, and protection against services failing elsewhere impacting our local systems. Local users are robust and simple, fast and easy. Until the 1990s it was rare to even consider the possibility of anything else.
Remotely managed users make up the overwhelming majority of cases today because this model allows for a single source...
