Oracle Database Discussions

platform: Oracle 10.2.0.1.0 on RHEL5.
Issue: tnsping failed from client (successful from the server itself)

Brief: I can tnsping and sqlplus to the test1 db from the RHEL5 db server itself, no issue. But when I tried to tnsping from a client, I get the error.
** In both db selver and the client, I am using same tnsnames.ora.
** checked etc/hosts , /etc/sysconfig/network , /proc/sys/net/ipv4/ip_local_port_range - all OK.

Pl help.

=======listener file======
LISTENER_TEST1 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = abc.com)(PORT = 1523))
)

SID_LIST_LISTENER_TEST1 =
(SID_LIST =
(SID_DESC =
(GLOBAL_DBNAME = test1)
(ORACLE_HOME = /app/oracle/product/10.2.0/db_1)
(SID_NAME = test1)
)
)
====================

=====tnsnames.ora=====
TEST1.ABC.COM =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = dbserver.abc.com)(PORT = 1523))
)
(CONNECT_DATA =
(SERVICE_NAME = test1)
)
)
====================


====================
----following is a tnsping test (SUCCESSFUL) from the db server itself----
dbserver> tnsping TEST1.ABC.COM

TNS Ping Utility for Linux: Version 10.2.0.1.0 - Production on 19-APR-2008 00:13:24

Copyright (c) 1997, 2005, Oracle. All rights reserved.

Used parameter files:
/app/oracle/product/10.2.0/db_1/network/admin/sqlnet.ora


Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = dbserver.abc.com)(PORT = 1523))) (CONNECT_DATA = (SERVICE_NAME = test1)))
OK (0 msec)
====================


====================
~~~~~Followin g is a tnsping test (FAILED) from a client~~~~~~~~~~
clientbox> tnsping test1.abc.com

TNS Ping Utility for Linux: Version 10.2.0.4.0 - Production on 19-APR-2008 00:22:09

Copyright (c) 1997, 2007, Oracle. All rights reserved.

Used parameter files:
/u01/app/oracle/product/10.2.0/network/admin/sqlnet.ora


Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = dbserver.abc.com)(PORT = 1523))) (CONNECT_DATA = (SERVICE_NAME = test1)))
TNS-12560: TNS:protocol adapter error
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
====================