ORA 12571 when expanding entry in DB Explorer


I’ve just installed SQL Navigator
Whenever I try to expand an entry in the DB Explorer like “Tables”, “Views”, … I get the “Synonyms” entry and then an “ORA-12571: TNS: packet writer failure” entry (this means that the error message does not appear in a separate window).
I’ll attach an hardcopy of the DB Explorer.

Everything works fine with SQL Navigator 5

Any hints on this?


Hi Marco,

Could you check in the relevant sqlnet.ora file whether you had this parameter

If so, then replace the value “NTS” with “NONE”, like this:


save the file, open SQL Nav 6.0 and try expand DB Explorer again.


Hi Andrew,

thanks for your answer.
Unfortunately I’m still getting the error.

Maybe this helps someone to solve my problem:
SQLNET.LOG in the SQL Nav. 6 directory says:

Fatal NI connect error 12203, connecting to:

TNS for 32-bit Windows: Version - Production
Oracle Bequeath NT Protocol Adapter for 32-bit Windows: Version - Production
Time: 12-NOV-2008 07:46:05
Tracing not turned on.
Tns error struct:
nr err code: 12203
TNS-12203: TNS:unable to connect to destination
ns main err code: 12560
TNS-12560: TNS:protocol adapter error
ns secondary err code: 0
nt main err code: 530
TNS-00530: Protocol adapter error
nt secondary err code: 0
nt OS err code: 0


I am going to throw something out, this may be way in left field, but did you check the Oracle Home client on the login screen. We had someone here who had a problem and it turned out they had the wrong default (I don’t believe they were having the same problem though).

Thanks Lozier for your answer, but selecting an explicit Oracle_Home did not help.

Hi Marco, It appears that you are connecting to unsupported Oracle version 8.0.6. You need to check which version of Oracle client is installed on your PC and whether it is compatible with 8.0.6 database. Please also, look at “Release Notes for SQL Navigator 6.0” for information System Requirements.

BTW Are you using SQL Nav to work with Oracle DevSuite? Do you have only one Oracle_Home? Not long ago, we had in this Forum a discussion of compatibility between Oracle Forms and SQL Nav connection manager. If you find this thread you may find something useful.

In long term, I believe, upgrading your Oracle will help SQL Nav 6.0 to work properly. Best wishes, Andrew

Message was edited by: akot

I’ve installed Oracle 9.02.

Now it works!
Thanks a lot!