The tnsnames.ora is a configuration file for Oracle database name resolution. It contains network service names that are mapped to connection descriptors for the local naming method. With the help of tnsnames.ora Oracle clients respectively the users can easily access Oracle databases. The connection descriptors provides all relevant information like host, Port, service name etc.
For larger environments with multiple Oracle databases and hundreds or more clients, managing and distributing the tnsnames.ora becomes cumbersome. The management of Oracle Net Service Names can be done with the following Oracle Solutions and Tools:
- Manual management of Oracle Net Service Names in one or more tnsnames.ora files. e.g. with a version control system, NFS share etc.
- Oracle Network Service Names can be entered directly in MS Active Directory. The database names are then resolved via AD. However, this method requires a schema extension in MS Active Directory. This is usually not so easy to implement in larger environments.
- Use of an Oracle Internet Directory (OID) for the directory based administration of Oracle Net Service Names. But OID is anything but lean.
It is also a good idea to directly implement Oracle Enterprise User Security based on Oracle Internet Directory or Oracle Unified Directory. Whereby with this solution a corresponding Oracle Directory Services Plus license is required. In addition, with Oracle Enterprise User Security, authentication and authorisation are also set up centrally. In addition to the license costs, there is also the increased implementation and operating costs. For the central administration of the Oracle Net Service Names a bit much effort. Especially if you want to use Oracle Centrally Managed Users instead of Oracle Enterprise User Security. As a simple alternative for the directory-based Oracle Net Service Names resolution, an open source LDAP directory service can of course always be used. A proven solution, just not officially supported by Oracle.
Since a few days Oracle has fulfilled my long awaited Christmas wish and adjusted the Restricted Use License for OUD and OID 
. The changes are available immediately for all current Oracle versions. I.e. Oracle 12.2, 18c, 19c and 21c. For the older database versions, e.g. 12.1 and 11.2 the restricted use licenses have not been adjusted.
This now allows the use of Oracle Unified Directory to build an LDAP directory for Oracle Net Service Names name resolution for any Oracle Edition except Oracle Database Express Edition. With the help of my scripts on GitHub oehrlis/oudbase you can build an OUD directory within a few minutes. I will give an example of this in a later blogpost.
Conclusion
Nothing stands in the way of setting up a simple LDAP directory service, based on Oracle Unified Directory, for Oracle Net Services name resolution. This is especially good news for larger environments and Oracle Centrally Managed Users deployments, where until now the only option was to manage the Oracle Net Service Names manually or to use an OpenSource LDAP directory service.
Links to the latest Oracle® Database Database Licensing Information User Manuals:
- Oracle® Database Database Licensing Information User Manual 21c
- Oracle® Database Database Licensing Information User Manual 19c
- Oracle® Database Database Licensing Information User Manual 18c
- Oracle® Database Database Licensing Information User Manual 12c Release 2 (12.2)
Have fun setting up your Oracle Unified Directory based Oracle Net Service Names server. Stay tuned for a couple of technical information and how-to’s ….