错误如下：
SQL> conn system/test@test
ERROR:
ORA-01034: ORACLE not available
ORA-27101: shared memory realm does not exist
Linux Error: 2: No such file or directory

1、检查了环境环境变量，查看了监听状态和实例状态都是正常的。
2、tnsping ZSK 也是通的

C:\>tnsping ZSK

TNS Ping Utility for 64-bit Windows: Version 10.2.0.4.0 - Production on 10-FEB-2012 22:51:55

Copyright (c) 1997,  2007, Oracle.  All rights reserved.

Used parameter files:
C:\oracle\product\10.2.0\db_1\network\admin\sqlnet.ora

Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.1)(PORT = 12521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = test)))
OK (20 msec)

C:\>

SQL> alter system set local_listener='(ADDRESS =(PROTOCOL=TCP)(HOST=134.224.55.118) (PORT=12521)(SID=ZSK))';
System altered.

SQL> alter system register;
System altered.

SQL> exit

客户端再次测试连接：
C:\>sqlplus system/test@test

SQL*Plus: Release 10.2.0.4.0 - Production on Fri Feb 10 22:54:49 2012

Copyright (c) 1982, 2007, Oracle.  All Rights Reserved.

Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL>