-A INPUT -p tcp -m state --state NEW -m tcp --dport 1521 -j ACCEPT

 -A INPUT -j REJECT --reject-with icmp-host-prohib

service  iptables  status        查看防火墙状态
service  iptables  start           开启防火墙
service  iptables  stop           关闭防火墙
service  iptables  restart        重启防火墙
 
 
这样启动后远程连接会报错:
oracle ORA-12514:TNS:listener does not currently know of service requested in connect descriptor

问题原因:数据库实例没注册到listener

解决方法一:

在listener.ora里面添加了一行

SID_LIST_LISTENER =  
(SID_LIST =  
  (SID_DESC =  
  (GLOBAL_DBNAME = orcl)
  (SID_NAME = orcl)
  )
)