If you try and create a new Oracle database (either using DBCA or manually) and get the
Oracle ORA-00600: internal error code, arguments: [keltnfy-ldmInit], , , , , , , 
error, this usually signifies that there was a problem resolving your server’s hostname.
Oracle needs to be able to resolve your server’s hostname from within the server on which you are installing Oracle. In case of the above error check your /etc/hosts file and verify that your server hostname is pingable.