Hi Friends, today i faced very nasty situation in establishing network connection with Oracle database.
I created a user as per request from application team and i got response that they are not able to connect. when analyzing i found tnsping is not working.
I started looking at tnsnames.ora and compared that with what is there in server and its same. so as next step i looked at SQLNET.ORA file and added following line to make sure both the machines are in same domain
NAMES.DEFAULT_DOMAIN = klpcph.local
I created a user as per request from application team and i got response that they are not able to connect. when analyzing i found tnsping is not working.
I started looking at tnsnames.ora and compared that with what is there in server and its same. so as next step i looked at SQLNET.ORA file and added following line to make sure both the machines are in same domain
NAMES.DEFAULT_DOMAIN = klpcph.local
Still nothing worked. Then i tried telnet from client machine and realized that 1521 port is blocked at firewall level.
Once firewall team provided access, tnsping worked but it throwed ORA-12638 : credential retrieval failed error
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I found following line in sqlnet.ora file on C:\app\teguh.triharto\product\11.2.0\dbhome_1\NETWORK\ADMIN
SQLNET.AUTHENTICATION_SERVICES= (NTS)
Then i modified the above line as below and it started working
SQLNET.AUTHENTICATION_SERVICES= (NONE)
this detail code Before Change
=================================================================================================
# sqlnet.ora Network Configuration File: C:\app\teguh.triharto\product\11.2.0\dbhome_1\network\admin\sqlnet.ora
# Generated by Oracle configuration tools.
# This file is actually generated by netca. But if customers choose to
# install "Software Only", this file wont exist and without the native
# authentication, they will not be able to connect to the database on NT.
SQLNET.AUTHENTICATION_SERVICES= (NTS)
NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)
=================================================================================================
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
=================================================================================================
this detail code after Change
# sqlnet.ora Network Configuration File: C:\app\teguh.triharto\product\11.2.0\dbhome_1\network\admin\sqlnet.ora
# Generated by Oracle configuration tools.
# This file is actually generated by netca. But if customers choose to
# install "Software Only", this file wont exist and without the native
# authentication, they will not be able to connect to the database on NT.
SQLNET.AUTHENTICATION_SERVICES= (NONE)
NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)
=================================================================================================
Reason :
Oracle client attempt to use your current Windows domain credentials to authenticate you with the Oracle server. This could fail for a couple of reasons:
- The Oracle server is not configured to support Windows authentication
- The credentials you use to login to your local machine are not sufficient to allow you to login to the server.
ORA-12638 : Credential retrieval failed
Cause : The authentication service failed to retrieve the credentials of a user.
Action : Enable tracing to determine the exact error.
In my case, it was the later. This failed because I was logged on to my local machine using my normal domain credentials rather than my administrator account.
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