ORA-12638: credential retrieval failed tips

Background:At the customer's site, the implementation team copied a copy of the Oracle-mounted Virtual Machine for testing.
Symptom:Since then the two servers are not available, the prompt "ORA-12638: credential retrieval failed Tips", when one of the machine is closed after some time will be good for a while, but occasionally will report an error, according to the error number, it is certain that this is not a problem of our program. We need to start with Oracle or the operating system.
Solution:Address: http://www.blogjava.net/decode360/archive/2008/10/20/286806.html

All things are not as difficult as you think. You can solve many problems as you do, ^ _ ^.

A ORA-12638 error was reported for no reason when I was connecting to SQL recently. It should be a permission issue, but it seems that no modification is made. I searched the internet and found that the solution to this problem is very simple, but it is mainly necessary to understand the meaning of the authentication_services parameter and record it here.

 

ORA-12638: credential retrieval failed tips

 

Oracle error tips by Stephen F. 
The Oracle docs note this on the ora-12638 error:

 

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.

 

On the Oracle technology network forums, an user is able to successfully resolve ORA-12638 after some help from repliers. 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 even finished.

 

A replier pointed out to the user that ORA-12638 is "an Oracle database error, indicating that the designer client was not able to connect to the database. "Though sometimes ORA-12638 can be resolved by restarting the database services in cases where oracle on Windows is being used, although for this user it was not helpful. however, the following direction was given, and once administered, was a successful resolution to ORA-12638: Please check the sqlnet. ora file. change the following entry and try, this will work.

 

Original entry-sqlnet. authentication_services = (ETS)
Modified entry-sqlnet. authentication_services = (none)

 

In terms of meaning, authentication_services =) only password verification is supported. However, the cause of Logon errors is complicated when the system is set to the ETS. You can refer to the following blog:

 

Http://zalbb.itpub.net/post/980/48931

 

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Some time ago, I installed a test database on MySQL 2003. Some colleagues reported this error when connecting to the database. I thought about it and found that I could not find the answer for a while. Later, I found that the sqlnet of the database was used. sqlnet. authentication_services can be used to overcome this error after being commented out, but the specific cause is still unclear. If this problem is not solved, I have been stunned. I remembered this problem two days ago and searched it on Google, I found an article on itpub, saying that it refers to the sqlnet of the client. delete the ora file and try it. But the person in the article could not explain the reason, and then asked Metalink, the Oracle technician gave me two articles to read first. After reading the test, I realized that I had a better understanding of the authentication method of the NTS.

 

Profiling of ora-12638 errors

 

Site (A, server) Windows 2003 (already a domain controller), oracle9206 (opatch5) site (B, client) Windows environment (), Oracle database or client

 

In site (A) and site (B), the oraclenetworkadmin directory contains the file sqlnet. ora. This file contains the sqlnet. authentication_services = (ETS)

 

Symptom 1: When site (B) logs on to the machine as the domain (this domain is different from the domain of site (a), and site (A), site (B) sqlnet. ora has this sqlnet. when authentication_services is used, the following error occurs:

 

SQL> connect Scott/1 @ Lenovo error:
ORA-12638: credential retrieval failed

 

Warning: you are no longer connected to Oracle. SQL>

 

Symptom 2: If the sqlnet. sqlnet. authentication_services is still commented out # sqlnet. authentication_services = (CNT) or sqlnet. authentication_services = (none), you can connect to the database normally

 

SQL> connect Scott/1 @ Lenovo
Connected.

 

Symptom 3: When the client site (B) logs on as a local user, no matter whether site (B)'s sqlnet. sqlnet. authentication_services = (CNT) is commented out # sqlnet. authentication_services = (CNT) or sqlnet. authentication_services = (none), can connect to the database normally

 

SQL> connect Scott/1 @ Lenovo
Connected.

 

Cause: site (a) is a domain controller (vsts.com). If site (B) is also logged on to the machine as a domain, and site (A), site (B) if operating system authentication is adopted, both parties need to establish a trust relationship. Otherwise, either party does not adopt the authentication. For example, sqlnet. authentication_services = none or # sqlnet. authentication_services = ***

 

Oracle is explained as follows:

 

Either create trust between the two domains or change the client or server sqlnet. authentication_services such that CNT in not negotiated in the connection handshake. CNT is only negotiated if both client and server have sqlnet. authentication_services set to ETS. i. e. sqlnet. authentication_services = none

 

Solution:

 

1. Build a trust relationship between the two domains (this method is not tested ).
2. sqlnet. authentication_services = none in the database or client sqlnet. ora or be commented out # sqlnet. authentication_services.