Ora 12638 credential retrieval failed ошибка

Problem

This technote explains why the error, ORA-12638: Credential retrieval failed, might occur when opening an IBM® Rational® RequisitePro® Oracle based project.

Cause

The full error message is as follows:

ORA-12638: Credential retrieval failed
- Oracle SQL*Net error
- Unable to connect to datasource


This error can be caused by incorrect configuration of the Oracle client sqlnet.ora file.

Resolving The Problem

To resolve this issue perform the following:

1. Locate the sqlnet.ora file on the client system which is by default stored in:
   
C:oracleoraXXnetworkadmin

2. Locate the following entry:
   
SQLNET.AUTHENTICATION_SERVICES= (NTS)

3. Replace the original entry with the following:
   
SQLNET.AUTHENTICATION_SERVICES= (NONE)


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

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

I found following line in sqlnet.ora file

SQLNET.AUTHENTICATION_SERVICES= (NTS)

Then i modified the above line as below and it started working

SQLNET.AUTHENTICATION_SERVICES= (NONE)

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.

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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• Question

• From Windows10 client, I received the error “ORA-12638:
  Credential retrieval failed” when I was trying to establish a connection to Oracle12c database using Oracle12c sqlplus.
  The error occur only when the attempt login, Windows account, is not under the same domain as the database. 

  On Windows7 client, ORA-12638 error NEVER occurs, whether the client and server domains are the same or different. 

   Configuration: 
      — SQLNET.AUTHENTICATION_SERVICES
  is set to NTS
      — Oracle Home user is Local System. 

   Environment (64-bit): 
      — Oracle Client 12.1.0.2 running on Windows 10 Enterprise version  
      — Oracle Database EE
  12.1.0.2 running on Windows Server 2012 R2 Standard version 

  From SQLNet client trace file, Kerberos authentication returned an error in InitializeSecurityContext as shown below.

  naun5authent: SPP is KERBEROS 
  naun5authent: SSPI: 0x80090342 error in InitializeSecurityContext 
  naun5authent: exit 
  naunauthent: exit 
  nau_ccn: get credentials function failed 
  nau_ccn: failed with error 12638 

  I can connect without the error by changing SQLNET.AUTHENTICATION_SERVICES
  to NONE.  However, this workaround is not feasible per my security policy.

  Question:
      1)  Do you have any suggestion/solution on the “SSPI: 0x80090342 error in InitializeSecurityContext” ?
      2)  Is there any difference between Windows 7 and Windows 10 regarding Kerberos authentication ?

Cause: The authentication service failed to retrieve the credentials of a user.

 

Action: Enable tracing to determine the exact error.

The original question was referring to a problem installing Oracle Designer, in which the user was thrown ORA-12638 when testing the connection, before the installation had completed.