最近在虚拟机上安装好oracle11g，然后将网卡模式从host -only模式切换到 桥接模式，OK

网卡正常切换，IP也获取到了，但是忘记将/etc/hosts里面的文件修改回来，然后，看下面

[oracle@normal ~]$ lsnrctl start

LSNRCTL for Linux: Version 11.2.0.3.0 - Production on 07-6月 -2016 13:08:46

Copyright (c) 1991, 2011, Oracle.  All rights reserved.

Starting /u01/app/product/11.2.0/bin/tnslsnr: please wait...

TNSLSNR for Linux: Version 11.2.0.3.0 - Production
Log messages written to /u01/app/diag/tnslsnr/normal/listener/alert/log.xml
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=normal)(PORT=1521)))

Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
TNS-12535: TNS:operation timed out
 TNS-12560: TNS:protocol adapter error
  TNS-00505: Operation timed out

新开一个终端，查看

[oracle@normal ~]$ lsnrctl

LSNRCTL for Linux: Version 11.2.0.3.0 - Production on 07-6月 -2016 13:09:17

Copyright (c) 1991, 2011, Oracle.  All rights reserved.

Welcome to LSNRCTL, type "help" for information.

LSNRCTL> status
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
TNS-12535: TNS:operation timed out
 TNS-12560: TNS:protocol adapter error
  TNS-00505: Operation timed out

查看listener.log日志

[oracle@normal trace]$ tail -f listener.log 
Tue Jun 07 13:09:47 2016
Log messages written to /u01/app/diag/tnslsnr/normal/listener/alert/log.xml
Trace information written to /u01/app/diag/tnslsnr/normal/listener/trace/ora_2547_139732456363776.trc
Trace level is currently 0

Started with pid=2547
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=normal)(PORT=1521)))
Listener completed notification to CRS on start

TIMESTAMP * CONNECT DATA [* PROTOCOL INFO] * EVENT [* SID] * RETURN CODE

卡在这里，不动！

仔细看上面的过程，发现HOST= 空，继而想到主机IP与hostname之间肯定存在问题。

然后找到hosts文件，一看，确实是因为现IP对应的主机名并不一致。

将ip与hostname配置一致，重启网卡后，listener正常。