In practice, most remote MySQL servers will block connections from client programs running on untrusted computers . Disallowing this type of connection
is a common security measure for MySQL servers used in production.
i don't know how to block connections from client programs,who can tell me how to do,thank you very much.
AFAIK MySQL blocks all connections not coming from localhost out of the box. No extra setup needed. Try it, get to another pc and try to connect the server.