How to Configure Monitoring in tnsnames. ora

tnsnames. ora Location: D:\ Installed\ oracle\ product\ 11.0\ db_1\ NETWORK\ ADMIN\ tnsnames.ora

You can only log in to the database after listening is configured

TOTO =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST =  This is IP Address )(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = SHARED)
      (SERVICE_NAME = toto)
    )
  )

Where HOST represents the ip address of the machine to be accessed and port is the port number. SERVICE_NAME corresponds to the database name.