ORA-12543: TNS:destination host unreachable

[oracle@rac2 bin]$tnsping oradb001
TNS Ping Utility for Linux: Version 11.2.0.1.0 - Production on 30-Nov-2012 01:52:34
Copyright (c) 1997, 2009, Oracle.  All rights reserved.
Used parameter files:
/oracle/11gdb/network/admin/sqlnet.ora

Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.1)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = oradb001)))

TNS-12543: TNS:destination host unreachable

Diagnosis process:

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Please use the oerr utility to get the more information on this error.

oracle@rac2 $ oerr ora 12543

12543, 00000, "TNS:destination host unreachable"

*Cause: Contact can not be made with remote party.

*Action: Make sure the network driver is functioning and the network is up.

Solution:
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Reason : Firewall was enabled on both the servers(rac1 & rac2).
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I disabled the firewall on both the servers.You can disable firewall by GUI and command line also.

root@rac1 # service iptables status
                     service iptables stop
                     chkconfig iptables off