ORA-12532: TNS:invalid argument

Solution : 1

This is the problem that caused the TNS-12532 error.  The SQL*Plus connect worked flawlessly and then started to throw the TNS-12532 error:

sqlplus user/password@devdb

SQL*Plus: Release 11.1.0.6.0 - Production on Wed May 19 15:32:40 2010

Copyright (c) 1982, 2007, Oracle.  All rights reserved.

ERROR:
ORA-12532: TNS:invalid argument

The resolution involved a system administration change.  The docs note this on the ORA-12532 error:

TNS-12532: TNS:invalid argument 

Cause: An internal function received an invalid parameter.

Action: Not normally visible to the user. For further details, turn on tracing and reexecute the operation. If error persists, contact Oracle Customer Support.

The system administrator had tightened up security on the remote machine (devdb) by implementing iptables and not allowed the other oracle hosts to connect on port 1521 (ssh was still open).

I added the following to the iptables:

-A INPUT -s vvv.xxx.yyy.zzz -p tcp -m state --state NEW -m tcp --dport 1521 -j ACCEPT

Solution:2

Bad password definition during creation of Oracle password file by using ORPWD utility may results to this error when connecting to the database using password file (e.g. remote login). I faced this problem when I was preparing auxiliary instance for database duplication process. Unknowingly, I created password file with bad password specification for user "SYS". I end up receiving ORA-12532: TNS: Invalid argument when attempting connecting to the auxiliary instance

For example: password specified here was "tiger@123" for user "SYS"

[oracle@Lugao-srv06 ~]$ orapwd file='/u01/app/oracle/product/11.2.0/dbhome_1/dbs/orapwHRMDB' entries=5 force=y

Enter password for SYS:

[oracle@Lugao-srv06 ~]$

Connecting to the database HRMDB with password "tiger@123" for user "SYS"

[oracle@Lugao-srv06 ~]$ sqlplus sys@HRMDB as sysdba

SQL*Plus: Release 11.2.0.1.0 Production on Thu Oct 3 13:40:24 2013

Copyright (c) 1982, 2009, Oracle.  All rights reserved.

Enter password:

ERROR:

ORA-12532: TNS:invalid argument

Enter user-name:

Creating password file with good password definition ("tiger#123") for user "SYS"

[oracle@Lugao-srv06 ~]$ orapwd file='/u01/app/oracle/product/11.2.0/dbhome_1/dbs/orapwHRMDB' entries=5 force=y

Enter password for SYS:

[oracle@Lugao-srv06 ~]$

Connecting to the database with newly created password

[oracle@Lugao-srv06 ~]$ sqlplus sys@HRMDB as sysdba

SQL*Plus: Release 11.2.0.1.0 Production on Thu Oct 3 13:42:00 2013

Copyright (c) 1982, 2009, Oracle.  All rights reserved.

Enter password:

Connected to:

Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production

With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL>                                

As the rule of thumb you should not use character @ in your password definition, because it is interpreted as special character,  ORPWD utility does not check this during password specification