Connect from Oracle 10 Client to Oracle19 Server giving "ORA-01017: invalid username/password; logon denied"

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Issue

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When connecting from Oracle 10 to Oracle 19, it is giving an error:
ORA-01017: invalid username/password; logon denied

But, when connecting with same credentials on the oracle 19 server, the connection is OK

-??!!

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How to fix

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Need to check value for PASSWORD_VERSIONS for the user in question

SELECT username, account_status, password_versions 

  FROM DBA_USERS 

 WHERE username = 'DBA_USER';

USERNAME          ACCOUNT_STATUS    PASSWORD_VERSIONS 
---------------   --------------    -----------------
DBA_USER          OPEN              11G 12C 

Connection from Oracle 10 Client would not be able to login.

Need to make password_versions compatible with 10g.

To fix:  edit sqlnet.ora:

SQLNET.ALLOWED_LOGON_VERSION = 8

SQLNET.ALLOWED_LOGON_VERSION_SERVER=8 

SQLNET.ALLOWED_LOGON_VERSION_CLIENT = 8

Then restart Listener.

Then reset/change the password for the user.

Now, the PASSWORD_VERSIONS allows connection from oracle 10.

ALTER USER DBA_USER IDENTIFIED BY NEW_USER_PASS;

SELECT username, account_status, password_versions 

  FROM DBA_USERS 

 WHERE username = 'DBA_USER';

USERNAME          ACCOUNT_STATUS    PASSWORD_VERSIONS 
---------------   --------------    -----------------
DBA_USER          OPEN              10G 11G 12C

===================

Additional Info

===================

A known issue

Due to security changes in authentication, starting from Oracle 12, it might be that users from Oracle Client with older version cannot login to newer Oracle Server.

To allow that:

Check 1 : SEC_CASE_SENSITIVE_LOGON = FALSE

Check 2:  PASSWORD_VERSIONS should be that of the Client

Oracle cannot be started due to error "ORA-07274: spdcr: access error, access to oracle denied."

====================

General

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Oracle cannot be started.

In alert.log, there is this error:

alert.log

Current log# 3 seq# 518649 mem# 0: /oracle_db/db1/db_igt/redo/redo03.log
2021-05-10T11:31:32.279377+00:00
Thread 1 advanced to log sequence 518650 (LGWR switch)
  Current log# 1 seq# 518650 mem# 0: /oracle_db/db1/db_igt/redo/redo01.log
2021-05-10T11:31:33.362773+00:00
Errors in file /software/oracle/diag/rdbms/igt/igt/trace/igt_psp0_5209.trc:
ORA-07274: spdcr: access error, access to oracle denied.
Linux-x86_64 Error: 2: No such file or directory
Errors in file /software/oracle/diag/rdbms/igt/igt/trace/igt_psp0_5209.trc  (incident=400034):
ORA-7274 [] [] [] [] [] [] [] [] [] [] [] []
Incident details in: /software/oracle/diag/rdbms/igt/igt/incident/incdir_400034/igt_psp0_5209_i400034.trc
2021-05-10T11:31:34.991651+00:00
USER (ospid: 5209): terminating the instance due to error 7274
2021-05-10T11:31:35.148877+00:00
System state dump requested by (instance=1, osid=5209 (PSP0)), summary=[abnormal instance termination].
System State dumped to trace file /software/oracle/diag/rdbms/igt/igt/trace/igt_diag_5240_20210510113135.trc
2021-05-10T11:31:41.045570+00:00


/software/oracle/diag/rdbms/igt/igt/trace/igt_psp0_5209.trc
error 7274 detected in background process
ORA-07274: spdcr: access error, access to oracle denied.
Linux-x86_64 Error: 2: No such file or directory
*** 2021-05-10T11:31:33.713353+00:00
2021-05-10T11:31:33.713285+00:00
Incident 400034 created, dump file: /software/oracle/diag/rdbms/igt/igt/incident/incdir_400034/igt_psp0_5209_i400034.trc
ORA-7274 [] [] [] [] [] [] [] [] [] [] [] []
2021-05-10 11:31:34.973 :kjzduptcctx(): Notifying DIAG for crash event
----- Abridged Call Stack Trace -----
ksedsts()+346<-kjzduptcctx()+868<-kjzdicrshnfy()+1113<-ksuitm_opt()+1678<-ksbrdp()+4494<-opirip()+609<-opidrv()+602<-sou2o()+145<-opimai_real()+202<-ssthrdmain()+417<-main()+262<-__libc_start_main()+245
----- End of Abridged Call Stack Trace -----
*** 2021-05-10T11:31:34.991458+00:00
USER (ospid: 5209): terminating the instance due to error 7274
ksuitm: waiting up to [5] seconds before killing DIAG(5240)

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Solution

====================

Check for missing binaries under $ORACLE_HOME/bin/

indeed - oracle executable was deleted during upgrade.

oracle@my_server:/software/oracle/196/bin>% ls -l
total 0
lrwxrwxrwx 1 oracle dba  8 Mar 26  2020 adrci -> ../adrci
lrwxrwxrwx 1 oracle dba  6 Mar 26  2020 exp -> ../exp
lrwxrwxrwx 1 oracle dba  8 Mar 26  2020 expdp -> ../expdp
lrwxrwxrwx 1 oracle dba  9 Mar 26  2020 genezi -> ../genezi
lrwxrwxrwx 1 oracle dba  6 Mar 26  2020 imp -> ../imp
lrwxrwxrwx 1 oracle dba  8 Mar 26  2020 impdp -> ../impdp
lrwxrwxrwx 1 oracle dba  9 Mar 26  2020 sqlldr -> ../sqlldr
lrwxrwxrwx 1 oracle dba 10 Mar 26  2020 sqlplus -> ../sqlplus
lrwxrwxrwx 1 oracle dba 10 Mar 26  2020 tnsping -> ../tnsping
lrwxrwxrwx 1 oracle dba 10 Mar 26  2020 uidrvci -> ../uidrvci
lrwxrwxrwx 1 oracle dba  6 Mar 26  2020 wrc -> ../wrc