Database ORACLE_HOME ................ /usr/oracle/app/oracle/product/11.2.0/dbhome_1
Local hostname ................ mydb.grp.local
Listener ORACLE_HOME ................ /usr/oracle/app/oracle/product/11.2.0/dbhome_1
Listener port number ................ 1521
Database SID ................ mydb

Caused by: oracle.sysman.emdrep.config.ConfigurationException: Cannot Create Connection:(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=mydb.grp.local)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=mydb.grp.local)))
SYSMAN
normal
ORA-00604: error occurred at recursive SQL level 1
ORA-20999: DB Access Restricted
ORA-06512: at line 60

java.sql.SQLException: ORA-00604: error occurred at recursive SQL level 1
ORA-20999: DB Access Restricted
ORA-06512: at line 60

--------------------------------------------------------------------
/etc/hosts file:-

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
129.1.1.6   mydb.grp.local     mydb
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

--------------------------------------------------------------------
lsnrctl status :-

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 11.2.0.1.0 - Production

Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=mydb.grp.local)(PORT=1521)))
Services Summary...
Service "mydb" has 1 instance(s).
  Instance "mydb", status UNKNOWN, has 1 handler(s) for this service...
Service "mydb.grp.local" has 1 instance(s).
  Instance "mydb", status READY, has 1 handler(s) for this service...
The command completed successfully
-------------------------------------------------------------------------------
listener.ora file:-
LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
      (ADDRESS = (PROTOCOL = TCP)(HOST = mydb.grp.local)(PORT = 1521))
    )
  )


ADR_BASE_LISTENER = /usr/oracle/app/oracle

SID_LIST_LISTENER =
  (SID_LIST =
     (SID_DESC =
         (SID_NAME = mydb)               
         (ORACLE_HOME = /usr/oracle/app/oracle/product/11.2.0/dbhome_1)
        )
  )

---------------------------------------------------------------------------------
tnsnames.ora file:-

MYDB =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = mydb.grp.local)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = mydb)
    )
  )

----------------------------------------------------------------------------------
sqlnet.ora file:-

NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)

ADR_BASE = /usr/oracle/app/oracle

shutdown immediate;
startup;