原因：
⒈网络不通
⒉客户端和服务器之间有防火墙
我的问题出在服务器的防火墙，xp自带的防火墙，只要在防火墙的例外添加1521断口规则就可以了
首先，ping数据库服务器的ip，通，物理链路上没有问题，
C:/>ping 192.168.0.55
Pinging 192.168.0.55 with 32 bytes of data:
Reply from 192.168.0.55: bytes=32 time<1ms TTL=128
Reply from 192.168.0.55: bytes=32 time<1ms TTL=128
Reply from 192.168.0.55: bytes=32 time<1ms TTL=128
Reply from 192.168.0.55: bytes=32 time<1ms TTL=128
Ping statistics for 192.168.0.55:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms
查看本机通信
C:/>ping 192.168.0.55
Pinging 192.168.0.55 with 32 bytes of data:
Reply from 192.168.0.55: bytes=32 time<1ms TTL=128
Reply from 192.168.0.55: bytes=32 time<1ms TTL=128
Reply from 192.168.0.55: bytes=32 time<1ms TTL=128
Reply from 192.168.0.55: bytes=32 time<1ms TTL=128
Ping statistics for 192.168.0.55:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms
C:/>netstat -an
Active Connections
Proto Local Address Foreign Address State
TCP 0.0.0.0:135 0.0.0.0:0 LISTENING
TCP 0.0.0.0:445 0.0.0.0:0 LISTENING
TCP 0.0.0.0:1046 0.0.0.0:0 LISTENING
TCP 0.0.0.0:1110 0.0.0.0:0 LISTENING
TCP 0.0.0.0:1521 0.0.0.0:0 LISTENING
TCP 0.0.0.0:1925 0.0.0.0:0 LISTENING
TCP 0.0.0.0:1929 0.0.0.0:0 LISTENING
TCP 0.0.0.0:3260 0.0.0.0:0 LISTENING
TCP 0.0.0.0:3261 0.0.0.0:0 LISTENING
TCP 0.0.0.0:4400 0.0.0.0:0 LISTENING
TCP 0.0.0.0:19780 0.0.0.0:0 LISTENING
TCP 127.0.0.1:1030 0.0.0.0:0 LISTENING
TCP 127.0.0.1:1030 127.0.0.1:1031 ESTABLISHED
TCP 127.0.0.1:1031 127.0.0.1:1030 ESTABLISHED
TCP 127.0.0.1:1034 0.0.0.0:0 LISTENING
TCP 127.0.0.1:1087 127.0.0.1:1110 CLOSE_WAIT
TCP 127.0.0.1:1110 127.0.0.1:1132 TIME_WAIT
TCP 127.0.0.1:1110 127.0.0.1:3118 ESTABLISHED
TCP 127.0.0.1:1110 127.0.0.1:3143 ESTABLISHED
TCP 127.0.0.1:1110 127.0.0.1:3766 ESTABLISHED
TCP 127.0.0.1:1110 127.0.0.1:4513 ESTABLISHED
TCP 127.0.0.1:1117 127.0.0.1:1110 TIME_WAIT
TCP 127.0.0.1:1125 127.0.0.1:1110 CLOSE_WAIT
TCP 127.0.0.1:1892 127.0.0.1:1110 CLOSE_WAIT
TCP 127.0.0.1:3118 127.0.0.1:1110 ESTABLISHED
TCP 127.0.0.1:3143 127.0.0.1:1110 ESTABLISHED
TCP 127.0.0.1:3766 127.0.0.1:1110 ESTABLISHED
TCP 127.0.0.1:3998 127.0.0.1:1110 CLOSE_WAIT
TCP 127.0.0.1:4105 127.0.0.1:1110 CLOSE_WAIT
TCP 127.0.0.1:4115 127.0.0.1:1110 CLOSE_WAIT
TCP 127.0.0.1:4169 127.0.0.1:1110 CLOSE_WAIT
TCP 127.0.0.1:4458 127.0.0.1:1110 CLOSE_WAIT
TCP 127.0.0.1:4513 127.0.0.1:1110 ESTABLISHED
TCP 127.0.0.1:4623 127.0.0.1:1110 CLOSE_WAIT
察看监听器
C:/>lsnrctl status
LSNRCTL for 32-bit Windows: Version 9.0.1.1.1 - Production on 16-7月 -2008 15:27
:13
Copyright (c) 1991, 2001, Oracle Corporation. All rights reserved.
正在连接到 (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=zhu)(PORT=1521)))
LISTENER 的 STATUS
------------------------
别名 LISTENER
版本 TNSLSNR for 32-bit Windows: Version 9.0.1.1.1 - Produc
tion
启动日期 16-7月 -2008 08:22:32
正常运行时间 0 天 7 小时 4 分 41 秒
跟踪级别 off
安全性 OFF
SNMP OFF
监听器参数文件 d:/oracle/ora90/network/admin/listener.ora
监听器日志文件 d:/oracle/ora90/network/log/listener.log
监听端点概要...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=zhu)(PORT=1521)))
服务摘要..
服务 "PLSExtProc" 包含 1 个例程。
例程 "PLSExtProc", 状态 UNKNOWN, 包含此服务的 1 个处理程序...
命令执行成功
TNSping TNS解析
C:/>tnsping orcl
TNS Ping Utility for 32-bit Windows: Version 9.0.1.1.1 - Production on 16-7月 -2
008 15:33:05
Copyright (c) 1997 Oracle Corporation. All rights reserved.
已使用的参数文件:
d:/oracle/ora90/network/admin/sqlnet.ora
d:/oracle/ora90/network/admin/tnsnames.ora
已使用 TNSNAMES 适配器来解析别名
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)
(HOST = 192.168.0.55)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = ORCL)))
TNS-12535: TNS: 操作超时
解析不成功，TNS。
Sql*plus
ERROR：
ORA-12535: TNS: 操作超时
警告: 您不再连接到 ORACLE。
SQL>
在服务器上找到sqlnet.log
位置：oracle_home/Db_1/network/log/sqlnet
***********************************************************************
Fatal NI connect error 12638, connecting to:
(DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))
VERSION INFORMATION:
TNS for 32-bit Windows: Version 10.1.0.2.0 - Production
Oracle Bequeath NT Protocol Adapter for 32-bit Windows: Version 10.1.0.2.0 - Production
Time: 15-7月 -2008 15:22:21
Tracing not turned on.
Tns error struct:
ns main err code: 12638
TNS-12638: Credential retrieval failed
ns secondary err code: 0
nt main err code: 0
nt secondary err code: 0
nt OS err code: 0
确定问题出在TNS上，就可以查看具体是在防火墙屏蔽了1521还是IP被人改过
★查找问题时候发现用
lsnrctl status
命令可以知道机器运行多久了。
这是一片更细的处理这个问题的方法，我只经历这一种障碍也紧谈谈自己的处理方法
转播
