Allow remote access to Oracle 12c

The error message means that one (or more) of the shared libraries required for TCP communications to work could not be loaded, perhaps due to o/s package updates? or it can mean that the /tmp/.oracle directory is not writeable by the oracle user (or doesn't exist perhaps because someone did some 'housekeeping' on /tmp . In either case tracing the listener at level 16 as Gaius suggested should reveal the issue.

Run:

lsnrctl status LISTENERNAME

... where LISTENERNAME is the name of the listener that is listening on port 1531. You can get this name from your $ORACLE_HOME/network/admin/listener.ora file.

For example:

LISTENER1531 =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS_LIST =
        (ADDRESS = (PROTOCOL = TCP)(HOST = node1)(PORT = 1531))
      )
    )
  )

LISTENER1531 would be the listener name for the above listener.ora entry.

If you need to add databases to the listener, add an entry to the listener.ora, as follows:

SID_LIST_LISTENER1531 =
  (SID_LIST =
    (SID_DESC =
      (GLOBAL_DBNAME = YOURDB)
      (ORACLE_HOME = /u01/app/oracle/product/11.2.0/dbhome_1)
      (PROGRAM = extproc)
      (SID_NAME = YOURDB)
    )
  )

Obviously you'll need to add your own database and listener names & change the path to your $ORACLE_HOME.

You can reload the listener config with:

lsnrctl reload LISTENER1531

The above works fine for me with a `tnsnames.ora as follows:

YOURDB =
 (DESCRIPTION =
   (ADDRESS_LIST =
     (ADDRESS = (PROTOCOL = TCP)(Host = node1)(Port = 1531))
   )
 (CONNECT_DATA =
   (SERVICE_NAME = YOURDB)
 )
)