Expert insights: Oracle NET troubleshooting for DBAs

Posted in: Oracle, Technical Track


Troubleshooting connection issues with Oracle SQL*Net can be difficult at times due to the many options that can be taken during configuration. One of the options is where the file tnsnames.ora may be found. There are multiple locations available, and at times there is justification for having more than one copy of the file.

Perhaps there is a hybrid database naming configuration. Say there are a number of company-wide databases that are defined in Oracle OID, OpenLDAP or Active Directory, while local test databases are defined in one or more local tnsnames.ora files.

When one of the databases appears to no longer be available, even though you are quite sure it should be available, it’s good to know the default search order used by Oracle to resolve the name.

The Oracle names resolution default search order for Linux and Windows is explained here:



But wait, there’s more!

You may know that on linux and unix systems tnsnames.ora can be placed in the /etc directory.

Do you know just what happens when /etc/tnsnames.ora is used?  Learn that and more by watching the rest of the presentation.


Discover more about our expertise in Oracle.

Want to talk with an expert? Schedule a call with our team to get the conversation started.

About the Author

Oracle experience: started with Oracle 7.0.13 Programming Experience: Perl, PL/SQL, Shell, SQL Also some other odds and ends that are no longer useful Systems: Networking, Storage, OS to varying degrees. Have fond memories of DG/UX

2 Comments. Leave new

Thanks for this share


Hello Jared,
Thanks for the new information.


Leave a Reply

Your email address will not be published. Required fields are marked *