It should accept connections only on the localhost interface.
In this start of our output script, we simply create variables to store our username and password for access to the database located at localhost.
仅当客户端应用程序运行在同一机器上并且通过环回地址(localhost或)连接时才能连接到该端口。
尽管，我们强烈建议在不同的机器上分离层，但是您可以使用一台机器运行样例，然后使用localhost替换上述每个给定地址。
