<div>
But Oracle Developer 6i is very old, right? Considered upgrading?
</div>


<div>
Author, any update to my comment please.
</div>


<div>
sorry for delay but i tried this option and i added this line <br />
<br />
SQLNET.ALLOWED_LOGON_VERSI<wbr />ON = 10 <br />
<br />
to sqlnet in server and client but same error appeared again <br />
<br />
and i using developer 6 from long time i will upgrade as soon as possible.
</div>


<div>
just &nbsp;i want to know some body connect developer 6i to oracle database under windows 8 or it is not compatible with windows 8 and cannot connect it to oracle 12c under windows 8
</div>


<div>
The problem solved <br />
<br />
the parameter value must be 8 <br />
SQLNET.ALLOWED_LOGON_VERSI<wbr />ON=8<br />
<br />
on server only <br />
<br />
<br />
<br />
Bug 14575666<br />
<br />
In 12.1, the default value for the SQLNET.ALLOWED_LOGON_VERSI<wbr />ON parameter has been updated to 11. This means that database clients using pre-11g JDBC thin drivers cannot authenticate to 12.1 database servers unless theSQLNET.ALLOWED_LOGON_VE<wbr />RSION parameter is set to the old default of 8.<br />
<br />
This will cause a 10.2.0.5 Oracle RAC database creation using DBCA to fail with the ORA-28040: No matching authentication protocol error in 12.1 Oracle ASM and Oracle Grid Infrastructure environments.<br />
<br />
Workaround: &nbsp;Set SQLNET.ALLOWED_LOGON_VERSI<wbr />ON=8 in the $crs_home/network/admin/sq<wbr />lnet.ora file.
</div>


<div>
<div class="content wysiwyg-content">
Hello, <br />
<br />
I installed oracle database 12c and installed oracle developer 6i <br />
on windows 8 operating system.<br />
When I try to connect developer to database the following error appeared <br />
<br />
ora-28040: no matching authentication protocol<br />
<br />
how to solve this error and connect developer to database?
</div>
</div>


Hello, 

I installed oracle database 12c and installed oracle developer 6i 
on windows 8 operating system.
When I try to connect developer to database the following error appeared 

ora-28040: no matching authentication protocol

how to solve this error and connect developer to database?

cannot connect oracle database to developer

Oracle is an object-relational database management system. It supports a large number of languages and application development frameworks. Its primary languages are SQL, PL/SQL and Java, but it also includes support for C and C++. Oracle also has its own enterprise modules and application server software.