[oracle@yao1 admin]$ tnsping ora10

TNS Ping Utility for Linux: Version 10.2.0.1.0 - Production on 17-MAY-2010 16:54:41

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

Used parameter files:

Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = 172.16.4.179)(PORT = 1529)) (CONNECT_DATA = (SERVER = DEDICATED) (SID = ora10)))
TNS-12560: TNS:protocol adapter error
主机B上重启监听lsnrctl stop正常

oracle@yao2 ~]$ lsnrctl start

LSNRCTL for Linux: Version 10.2.0.1.0 – Production on 17-MAY-2010 16:57:44

Copyright (c) 1991, 2005, Oracle. All rights reserved.

Starting /oracle/product/10.2.0/db_1/bin/tnslsnr: please wait…

TNSLSNR for Linux: Version 10.2.0.1.0 – Production
System parameter file is /oracle/product/10.2.0/db_1/network/admin/listener.ora
Log messages written to /oracle/product/10.2.0/db_1/network/log/listener.log
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1)))
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=172.16.4.179)(PORT=1529)))

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1)))
STATUS of the LISTENER
————————
Alias LISTENER
Version TNSLSNR for Linux: Version 10.2.0.1.0 – Production
Start Date 17-MAY-2010 16:57:46
Uptime 0 days 0 hr. 0 min. 0 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /oracle/product/10.2.0/db_1/network/admin/listener.ora
Listener Log File /oracle/product/10.2.0/db_1/network/log/listener.log
Listening Endpoints Summary…
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=172.16.4.179)(PORT=1529)))
Services Summary…
Service “PLSExtProc” has 1 instance(s).
Instance “PLSExtProc”, status UNKNOWN, has 1 handler(s) for this service…
Service “ora10″ has 1 instance(s).
Instance “ora10″, status UNKNOWN, has 1 handler(s) for this service…
The command completed successfully

本机B tnsping自己正常，tnsping A也正常，而其他所有主机tnsping 都出现如上错误，tnsname.ora 设置正常，端口修改也不能解决远程主机Atnsping B成功。

最后发现是 主机A服务器防火墙已经关闭，而主机B上防火墙没有关闭进行如下操作

[root@localhost ~]# service iptables stop
Flushing firewall rules: [ OK ]

Setting chains to policy ACCEPT: filter [ OK ]

Unloading iptables modules: [ OK ]

防火墙关闭后一切正常。