ORA-12170:TNS:Connect timeout occurred

  

现象：
使用第三方工具PL/SQL Developer和Toad均无法远程连接数据库，报错均为：ORA-12170:TNS:Connect timeout occurred




[oracle@localhost dbs]$ lsnrctl status


LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 12-JUN-2014 11:42:52


Copyright (c) 1991, 2009, Oracle.  All rights reserved.


Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 11.2.0.1.0 - Production
Start Date                12-JUN-2014 11:22:22
Uptime                    0 days 0 hr. 20 min. 29 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /oracle/product/11.2.0/network/admin/listener.ora
Listener Log File         /oracle/diag/tnslsnr/localhost/listener/alert/log.xml
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=localhost)(PORT=1521)))
Services Summary...
Service "VCDB" has 3 instance(s).
  Instance "VCDB", status UNKNOWN, has 1 handler(s) for this service...
  Instance "VCDB", status BLOCKED, has 1 handler(s) for this service...
  Instance "VCDB", status READY, has 1 handler(s) for this service...
Service "VCDBXDB" has 1 instance(s).
  Instance "VCDB", status READY, has 1 handler(s) for this service...
The command completed successfully
[oracle@localhost dbs]$ 




既有动态注册也有静态注册信息。




原因：
数据库服务器的防火墙导致的无法连接问题，应该是在系统安装的时候没有关掉防火墙。


解决方法：
执行命令service iptables stop 之后便可以正常连接。