在oracle的监听如果出现TNS-12537, TNS-12560, TNS-00507 Linux Error: 29: Illegal seek error When Starting the Listener问题，如下图：
请修改/etc/hosts，保证如下图，这样监听才能正常启动
$ lsnrctl start
LSNRCTL for LINUX: Version 10.1.0.4.0 - Production on 01-JUL-2005 10:16:59
Copyright (c) 1991, 2004, Oracle. All rights reserved.
Starting /db02/product/10.1/bin/tnslsnr: please wait...
TNS-12537: TNS:connection closed
TNS-12560: TNS:proto adapter error
TNS-00507: Connection closed
HPUX Error: 29: Illegal seek
Changes
Verify the user attempting to start the TNS Listener process has read permissions on the /etc/hosts file, and that this file contains the localhost entry:
127.0.0.1 localhost.localdomain localhost -----保证含有这条记录
192.168.2.20 single.oracle.com single .
