ORA-28040: No matching authentication protocol

Question

I am facing this issue even after following the below settings.

1. Replacing ojdbc14.jar with ojdbc6.jar[also tried ojdbc5.jar<

Answer 1

ORA-28040: No matching authentication protocol

I faced a similar issue when trying to connect a

32-bit Oracle 11g Client to a 64-bit Oracle 12c Server

I then proceeded to add the following to sqlnet.ora

SQLNET.ALLOWED_LOGON_VERSION_CLIENT = 8
SQLNET.ALLOWED_LOGON_VERSION_SERVER = 8

I then experienced the following error

ORA-01017: invalid username/password: logon denied

Adding the following to the Client sqlnet.ora as well as the Server, I was able to connect an old version of Toad and PL/SQL to the new 12c Server.

SQLNET.AUTHENTICATION_SERVICES = (NONE)