Recently after I configured database on testing machine and configure the forms to run on middle tier on testing machine (all windows environment), I came across the error ORA-12638.
After little bit of brains storming and checking online, I found out that one of the way to solve this error is to disable the Oracle Advanced Security Authentication and let database use the supplied user name and password to authenticate.
It can be disable by updating the sqlnet.ora file with the following entry:
SQLNET.AUTHENTICATION_SERVICES = (NONE)
Note : Default entry in my case was SQLNET.AUTHENTICATION_SERVICES= (NTS)
Guys do check out other method and let me know.
Any way the above method worked for me and I am happy with that at least by Monday morning, my system will be available for testing purpose 
5 responses so far ↓
1 Vinayaka Paradkar // May 20, 2008 at 12:07 am
This is awesome, It worked for me as well!
Thanks a lot
2 Sean Liesenberg // May 22, 2008 at 5:05 am
Note that I get this as well but I cannot change my SQLNET.AUTHENTICATION_SERVICES = (NTS) as we use NT Authentication to validate the user. This is a requirement at the company.
Is there any alternative to not getting this error?
3 Rajender Singh // May 27, 2008 at 12:36 am
Hi Sean,
This thing succeed at my side so didn’t though of anything else at moment.
Any ways guys please do input if you have come across such instance.
Thanks & Regards,
Rajender
4 Sean Liesenberg // May 27, 2008 at 8:43 pm
Note that our corporate settings are actually:
SQLNET.AUTHENTICATION_SERVICES= (NTS, NONE)
Yet I still get this error from time to time.
Any help would be greatly appreciated.
5 Rajender Singh // May 28, 2008 at 11:29 am
Hi Sean,
Try setting SQLNET.AUTHENTICATION_SERVICES = (NONE) at client side.
One more thing, there is no harm is setting SQLNET.AUTHENTICATION_SERVICES = (NTS) and it should work.
Check out Server and the Client Machine which you are trying to connect are in same domain or not.
Regards,
Rajender
Leave a Comment