Public, create

SQL>
CREATE PUBLIC DATABASE LINK TODBNAME
CONNECT TO DBMANE IDENTIFIED BY somepassword
USING '(DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.77)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = DBNMAE)))';

Public, check

SQL> select * from dual@ TODBNAME;                       TODBNAME - is a DB_LINK name,not username	'X' symbol must be as query result