Db aliases are used as additional level of addressing databases in connection strings: having alias you may change real db instance or even server name without reconfiguration of your apps, because alias will remain the same. But if you see connection string like that:
Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=MyDatabase;Data Source=test
where “test” specified in Data Source is db alias, how to know to what db instance specified alias belongs to?
The easiest way is to use cliconfg tool. When you run it on the Alias tab you will see list of all used db aliases and real db instances they belong to: