Errors ORA-12154, ORA-29003 when connecting to Autonomous Data Warehouse using Django

When connection to Autonomous Data Warehouse Using Django web framework first we come across “ORA-12154” error. That means Django cannot be able to connect to the Oracle Database service name with the settings in settings.py file.

File "C:\django\db\backends\oracle\base.py", line 254, in get_new_connection return Database.connect( cx_Oracle.DatabaseError: ORA-12154: TNS:could not resolve the connect identifier specified

First copy the tnsnames.ora into local system and test tnsping.

C:\> tnsping <service Name>

If the tnsping is working fine, then below are the passible reason for ORA-12154 error

• TNS_ADMIN might not be configured or set the right path
• There might be a typo in service name
• Connection details in settings.py might not be correct

We found that TNS_ADMIN is not set to the right path and updating the correct path resolved the issue. But we have received new error

ORA-29003: SSL transport detected mismatched server certificate

Django supports Oracle Database 19c or higher versions but cx_oracle python driver required. We verified that required driver is installed. We try to connect using SQL*PLUS but still receiving same error. That means there is no issue with the settings.

After research we found that 12c client is not supported for new mTLS authentication as per document “ALERT: Action Required for Autonomous Databases (Doc ID 2911553.1)”

We have installed Oracle 19c client and were able to connect without any issues.

Below are the options to resolve the issue

1. Install certified oracle client versions 11.2.0.4.220719 (or later), 18.19 (or later), 19.2 (or later), 21 (base release or later)

2. Update Autonomous database instance to allow both TLS and mTLS authentication.

• Goto Autonomous Database Details page --> Network --> click Edit in the Mutual TLS (mTLS) Authentication field.
• Change the value to allow TLS authentication, deselect Require mutual TLS (mTLS) authentication
• Click Update

3. Use ssl_server_dn_match=no in the connect string (when using 12c client updating the value to “no” didn’t help )

I hope this helps.

Thanks
Satishbabu G, Oracle ACE Pro

https://oracleracexpert.com