Translations:PostgreSQL/QuickStart/51/en

As has been mentioned before, by default the server is secure. Kind of. There is only one database role that is available for log in by default: postgres. And, the only way to initiate a connection to the database is through the Unix socket, which is owned by the postgres system user and system group, or via localhost. Now for the "kind of" bit: Any user on the system can make a connection to the database through the localhost. Even as the postgres database superuser.