hosts文件权限导致监听无法启动

1.所属系统：
2.问题描述：
3.解决
4.参考
？？？疑点：为什么修改主机名会使hosts文件权限发生改变

1.所属系统：

ZHJS2#[/]uname -a
HP-UX ZHJS2 B.11.31 U ia64 2866286647 unlimited-user license

2.问题描述：

修改主机名后，数据库监听无法启动，查看listener.ora文件如下：

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = ZHJS2)(PORT = 1521)) 
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
    )
  )
ADR_BASE_LISTENER = /Oracle
SID_LIST_LISTENER =
  (SID_LIST=
      (SID_DESC=
          (SID_NAME=ZHJS2)
             (ORACLE_HOME=/Oracle/product/11.2.0.3/dbhome_1)
        )
  )

使用lsnrctl start启动的时候报无法识别主机名，但是在操作系统级别使用hostname查看确实是ZHJS2，和/etc/hosts文件也可以对应，为什么会报无法识别呢？
然后干脆不适用主机名，把HOST后面直接加IP地址，依然不行，如下：

ZHJS2$[/Oracle]lsnrctl 
LSNRCTL for HPUX: Version 11.2.0.3.0 - Production on 09-MAR-2016 20:32:58
Copyright (c) 1991, 2011, Oracle.  All rights reserved.
Welcome to LSNRCTL, type "help" for information.
LSNRCTL> status
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=132.32.24.7)(PORT=1521)))
TNS-12541: TNS:no listener
 TNS-12560: TNS:protocol adapter error
  TNS-00511: No listener
   HPUX Error: 239: Connection refused
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1521)))
TNS-12541: TNS:no listener
 TNS-12560: TNS:protocol adapter error
  TNS-00511: No listener
   HPUX Error: 239: Connection refused
LSNRCTL> start
Starting /Oracle/product/11.2.0.3/dbhome_1/bin/tnslsnr: please wait...
TNS-12537: TNS:connection closed
 TNS-12560: TNS:protocol adapter error
  TNS-00507: Connection closed
   HPUX Error: 29: Illegal seek

报：TNS-12537 TNS-00507

3.解决

经过一段时间的排查和尝试以及和其他机器相比，发现oracle用户无法读取hosts文件，查看hosts文件权限

ZHJS2#[/]ls -l /etc/hosts
-rw-------   1 root       sys           1256 Mar  9 20:23 /etc/hosts
**修改hosts文件权限**
ZHJS2#[/]chmod 644 /etc/hosts

修改后再次启动监听，成功！！！

4.参考

My support oracle :ID 315720.1

Verify the user attempting to start the TNS Listener process has read permissions on the /etc/hosts file, and that the /etc/hosts file contains the localhost entry in the following form:

127.0.0.1 localhost.localdomain localhost 
12.123.123.12 myhost.us.oracle.com myhost

？？？疑点：为什么修改主机名会使hosts文件权限发生改变

来自为知笔记(Wiz)