I am a beginner to computer networking. Help me understand how the following scenario can be modelled.
A company has three employees,say , X, Y and Z. X sits in New York, Y sits in California and Z sits in London. Let's say the a database server is set up in X's home(what happens if X has only a normal DSL modem ?) . How do we make sure that ONLY Y and Z sitting in different parts of the world access the database at X's home.
What is the minimum infrastructure needed to set up this thing ? What are the technical details that go into this ? Is having an internet connection just enough ?