[oracle11g@testdb2 dbs]$ sqlplus "/ as sysdba"
 
SQL*Plus: Release 11.2.0.4.0 Production on Mon Apr 21 13:48:32 2014
 
Copyright (c) 1982, 2013, Oracle.  All rights reserved.
 
Connected.
SQL> startup nomount
ORA-00000: normal, successful completion
SQL> alter database mount;
ERROR:
ORA-01012: not logged on
 
SQL> 
 
[root@testdb2 etc]# cat hosts
# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.56.250 wrong_server
#192.168.56.132 testdb2

[root@testdb2 etc]# cat hosts
# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
#192.168.56.250 wrong_server
192.168.56.132 testdb2
 
再次启动：
SQL> startup nomount
ORACLE instance started.
 
Total System Global Area 1052274688 bytes
Fixed Size                  2259840 bytes
Variable Size            1023411328 bytes
Database Buffers           20971520 bytes
Redo Buffers                5632000 bytes
SQL> 
 
正常。