一组的同事找我说，有很多应用不能连接数据库，让我去帮忙看看，一开始以为是process 和session 数不构，去了查了一下，发现远没到设置的数，且主机未发现有性能问题，查看等待事件，全是军空闲类的，这下我就有点朦了，后来查看监听状态，执行lsnrctl status 后出来两行字之后卡在那儿了，没有反应，所以kill掉进程后重启监听，重启后，没有服务注册时正常，过1分种在查看监听状态，还是卡在那儿了，查看监听日志没什么收获，后来查看数据库alter日志，发现如下：
Fatal NI connect error 12537, connecting to:
(LOCAL=NO)
VERSION INFORMATION:
TNS for Linux: Version 11.2.0.1.0 - Production
Oracle Bequeath NT Protocol Adapter for Linux: Version 11.2.0.1.0 - Production
TCP/IP NT Protocol Adapter for Linux: Version 11.2.0.1.0 - Production
Time: 03-NOV-2014 09:44:15
Tracing not turned on.
Tns error struct:
ns main err code: 12537
TNS-12537: TNS:connection closed
ns secondary err code: 12560
nt main err code: 0
nt secondary err code: 0
nt OS err code: 0
opiodr aborting process unknown ospid (3657) as a result of ORA-609
Mon Nov 03 09:44:22 2014
***********************************************************************
Fatal NI connect error 12537, connecting to:
(LOCAL=NO)
VERSION INFORMATION:
TNS for Linux: Version 11.2.0.1.0 - Production
Oracle Bequeath NT Protocol Adapter for Linux: Version 11.2.0.1.0 - Production
TCP/IP NT Protocol Adapter for Linux: Version 11.2.0.1.0 - Production
Time: 03-NOV-2014 09:44:22
Tracing not turned on.
Tns error struct:
ns main err code: 12537
TNS-12537: TNS:connection closed
ns secondary err code: 12560
nt main err code: 0
nt secondary err code: 0
nt OS err code: 0
opiodr aborting process unknown ospid (3666) as a result of ORA-609
Mon Nov 03 09:44:26 2014
***********************************************************************
Fatal NI connect error 12537, connecting to:
(LOCAL=NO)
VERSION INFORMATION:
TNS for Linux: Version 11.2.0.1.0 - Production
Oracle Bequeath NT Protocol Adapter for Linux: Version 11.2.0.1.0 - Production
TCP/IP NT Protocol Adapter for Linux: Version 11.2.0.1.0 - Production
Time: 03-NOV-2014 09:44:26
Tracing not turned on.
Tns error struct:
ns main err code: 12537
TNS-12537: TNS:connection closed
ns secondary err code: 12560
nt main err code: 0
nt secondary err code: 0
nt OS err code: 0
opiodr aborting process unknown ospid (3670) as a result of ORA-609
Mon Nov 03 09:44:27 2014
***********************************************************************
Fatal NI connect error 12537, connecting to:
(LOCAL=NO)
VERSION INFORMATION:
TNS for Linux: Version 11.2.0.1.0 - Production
Oracle Bequeath NT Protocol Adapter for Linux: Version 11.2.0.1.0 - Production
TCP/IP NT Protocol Adapter for Linux: Version 11.2.0.1.0 - Production
Time: 03-NOV-2014 09:44:27
Tracing not turned on.
Tns error struct:
ns main err code: 12537
TNS-12537: TNS:connection closed
ns secondary err code: 12560
nt main err code: 0
nt secondary err code: 0
nt OS err code: 0
opiodr aborting process unknown ospid (3695) as a result of ORA-609
上网查了一下，有人说是DNS解析问题，按照解决方法注释DNS 的解析后工作正常，上网查了很多，没有发现具体原因。
解决方法
注释掉 /etc/resolve.conf 配置文件中对 DNS 的解析解决