建了一个库，想通过Oracle Net访问，需要配置监听器和tnsnames.ora，接下来碰到一系列的问题。。。
1. 添加监听器配置，listener.ora文件默认包括：
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
)
)
ADR_BASE_LISTENER = /opt/app/ora11g
为了新建监听器名称，添加如下：
DCSOPEN =
(ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(Host = 172.101.19.57)(Port = 1521)))
或
DCSOPEN =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = dcsopen2Node)(PORT = 1521))
)
)
ADR_BASE_DCSOPEN = /opt/app/ora11g
或
DCSOPEN =
(ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(Host = 172.101.19.57)(Port = 1521)))
SID_LIST_DCSOPEN =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = /opt/app/ora11g/product/11.2.0/dcsopen)
(PROGRAM = extproc)
)
(SID_DESC =
(GLOBAL_DBNAME = dcsopen)
(ORACLE_HOME = /opt/app/ora11g/product/11.2.0/dcsopen)
(SID_NAME = dcsopen)
)
)
ADR_BASE_DCSOPEN = /opt/app/ora11g
或
DCSOPEN =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 172.101.19.57)(PORT = 1521))
)
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC))
)
)
)
SID_LIST_DCSOPEN =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = /opt/app/ora11g/product/11.2.0/dcsopen)
(PROGRAM = extproc)
)
)
ADR_BASE_DCSOPEN = /opt/app/ora11g
2. 添加本机的tnsnames.ora文件配置：
dcsopen =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 172.101.19.57)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = dcsopen)
)
)
3. 使用tnsping dcsopen测试，报错：
ora11g>tnsping dcsopen
TNS Ping Utility for Linux: Version 11.2.0.1.0 - Production on 08-JAN-2015 00:38:55
Copyright (c) 1997, 2009, Oracle. All rights reserved.
Used parameter files:
/opt/app/ora11g/product/11.2.0/dcsopen/network/admin/sqlnet.ora
TNS-03505: Failed to resolve name
4. 使用sqlplus登录测试，报错：
ora11g>sqlplus dcsopen/dcsopen1@dcsopen
SQL*Plus: Release 10.2.0.1.0 - Production on Mon Sep 13 23:11:00 2010
Copyright (c) 1982, 2005, Oracle. All rights reserved.
ERROR:
ORA-12154: TNS:could not resolve the connect identifier specified
Enter user-name:
5. 检查监听器状态，
ora11g>lsnrctl status
LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 08-JAN-2015 01:55:32
Copyright (c) 1991, 2009, Oracle. All rights reserved.
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 11.2.0.1.0 - Production
Start Date 07-JAN-2015 20:19:09
Uptime 0 days 5 hr. 36 min. 23 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /opt/app/ora11g/product/11.2.0/dcsopen/network/admin/listener.ora
Listener Log File /opt/app/ora11g/diag/tnslsnr/dcsopen2Node/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=dcsopen2Node)(PORT=1521)))
...
并未看到dcsopen的配置。
6. 开启trace，查看tnsping失败的原因：
创建sqlnet.ora文件：
# sqlnet.ora Network Configuration File: /opt/oracle/102/network/admin/sqlnet.ora
# Generated by Oracle configuration tools.
NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)
Trace_level_client=16
Trace_directory_client=/opt/app/ora11g/product/11.2.0/dcsopen/network/admin
Trace_unique_client=on
Trace_timestamp_client=on
Diag_adr_enabled=off
tnsping.trace_directory=/opt/app/ora11g/product/11.2.0/dcsopen/network/admin
tnsping.trace_level=admin
执行tnsping报错后，查看tnsping.trc文件：
tail: tnsping.trc: file truncated
TNS Ping Utility for Linux: Version 11.2.0.1.0 - Production on 07-JAN-2015 19:21:31
Copyright (c) 1997, 2009, Oracle. All rights reserved.
--- TRACE CONFIGURATION INFORMATION FOLLOWS ---
New trace stream is /opt/app/ora11g/product/11.2.0/dcsopen/network/admin/tnsping.trc
New trace level is 6
--- TRACE CONFIGURATION INFORMATION ENDS ---
--- PARAMETER SOURCE INFORMATION FOLLOWS ---
Attempted load of system pfile source /opt/app/ora11g/product/11.2.0/dcsopen/network/admin/sqlnet.ora
Parameter source loaded successfully
-> PARAMETER TABLE LOAD RESULTS FOLLOW <-
Successful parameter table load
-> PARAMETER TABLE HAS THE FOLLOWING CONTENTS <-
Diag_adr_enabled = off
tnsping.trace_level = admin
Trace_level_client = 16
NAMES.DIRECTORY_PATH = (TNSNAMES, EZCONNECT)
tnsping.trace_directory = /opt/app/ora11g/product/11.2.0/dcsopen/network/admin
Trace_unique_client = on
Trace_directory_client = /opt/app/ora11g/product/11.2.0/dcsopen/network/admin
Trace_timestamp_client = on
--- PARAMETER SOURCE INFORMATION ENDS ---
--- LOG CONFIGURATION INFORMATION FOLLOWS ---
Log stream will be "standard output"
Log stream validation not requested
--- LOG CONFIGURATION INFORMATION ENDS ---
nlstdipi: entry
nlstdipi: exit
nnfun2awanm: entry
nnfgiinit: entry
nncpcin_maybe_init: default name server domain is [root]
nnfgiinit: Installing read path
nnfgsrsp: entry
nnfgsrsp: Obtaining path parameter from names.directory_path or native_names.directory_path
nnfgsrdp: entry
nnfgsrdp: Setting path:
nnfgsrdp: checking element TNSNAMES
nnfgsrdp: checking element EZCONNECT
nnfgsrdp: Path set
nnfun2a: entry
nlolgobj: entry
nnfgrne: entry
nnfgrne: Going though read path adapters
nnfgrne: Switching to TNSNAMES adapter
nnftboot: entry
nlpaxini: entry
nlpaxini: exit
nnftmlf_make_local_addrfile: entry
nnftmlf_make_local_addrfile: construction of local names file failed
nnftmlf_make_local_addrfile: exit
nlpaxini: entry
nlpaxini: exit
nnftmlf_make_system_addrfile: entry
nnftmlf_make_system_addrfile: system names file is /opt/app/ora11g/product/11.2.0/dcsopen/network/admin/tnsnames.ora
nnftmlf_make_system_addrfile: exit
nnftboot: exit
nnftrne: entry
nnftrne: Original name: dcsopen
nnfttran: entry
nnfgrne: Query unsuccessful, skipping to next adapter
nnfgrne: Switching to EZCONNECT adapter
nnfhboot: entry
nnfhboot: exit
snlinGetAddrInfo: entry
snlinGetAddrInfo: getaddrinfo() failed with error -3
snlinGetAddrInfo: exit
nnfgrne: Query unsuccessful, skipping to next adapter
nnfgrne: exit
nnfun2a: address for name "dcsopen" not found
nnfun2awanm: Getting the path of sqlnet.ora
nnfun2awanm: Getting the path of local and system tnsnames.ora
nnfun2awanm: exit
nlse_term_audit: entry
nlse_term_audit: exit
可以看到其中出现的一些错误：
construction of local names file failed
Query unsuccessful, skipping to next adapter
getaddrinfo() failed with error -3
address for name "dcsopen" not found
直观看，没有识别出dcsopen监听。
后来查询MOS有篇文章(Client Connections Fail With TNS-12154 / ORA-12154 (文档 ID 1150680.1))
说这个情况的原因可能是：This means Oracle Net is unable to read the file correctly or entry inside the file.
解决方法是：Rebuild the TNSNAMES.ORA file, using the GUI Net Manager tool, is the recommend solution. This will ensure there are no mistakes in the net admin file, for example, brackets, tab, spacing, etc. Also
ensure the tnsnames.ora file can be read by the oracle user.
6. 于是先使用图形化netca创建dcsopen的监听项错误依旧，经过一系列测试，确定了文件listener.ora：
# listener.ora Network Configuration File: /opt/app/ora11g/product/11.2.0/dcsopen/network/admin/listener.ora
# Generated by Oracle configuration tools.
DCSOPEN =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 172.101.19.57)(PORT = 1521))
)
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC))
)
)
)
SID_LIST_DCSOPEN =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = /opt/app/ora11g/product/11.2.0/dcsopen)
(PROGRAM = extproc)
)
)
ADR_BASE_DCSOPEN = /opt/app/ora11g
其中：
(1) 参考eygle的经验，使用动态注册服务。
(指当实例启动后，由后台进程PMON在监听器中注册数据库服务信息。动态注册机制下，原来监听器中的SID_LIST部分将不再需要。)
(2) 上面之所以还有一个SID_LIST，这是缺省的PLSExtProc是为外部存储过程调用而配置。一个简单的监听器配置如上所述。
启动监听，提示：
ora11g>lsnrctl status
LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 08-JAN-2015 01:55:32
Copyright (c) 1991, 2009, Oracle. All rights reserved.
Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 11.2.0.1.0 - Production
Start Date 07-JAN-2015 20:19:09
Uptime 0 days 5 hr. 36 min. 23 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File /opt/app/ora11g/product/11.2.0/dcsopen/network/admin/listener.ora
Listener Log File /opt/app/ora11g/diag/tnslsnr/dcsopen2Node/listener/alert/log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=dcsopen2Node)(PORT=1521)))
Services Summary...
Service "dcsopen" has 1 instance(s).
Instance "dcsopen", status
READY, has 1 handler(s) for this service...
Service "dcsopenXDB" has 1 instance(s).
Instance "dcsopen", status READY, has 1 handler(s) for this service...
The command completed successfully
本机测试tnsping正常了。
7. 接着，使用netca新增tnsnames.ora文件：
# tnsnames.ora Network Configuration File: /opt/app/ora11g/product/11.2.0/dcsopen/network/admin/tnsnames.ora
# Generated by Oracle configuration tools.
DCSOPEN =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 172.101.19.57)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = dcsopen)
)
)
本机测试sqlplus ...@dcsopen正常了。
8. 从另外一台机器访问这个数据库dcsopen，修改tnsnames.ora文件，执行tnsping dcsopen报错：
ora10g@localhost.localdomain$tnsping dcsopen
TNS Ping Utility for Linux: Version 10.2.0.1.0 - Production on 08-JAN-2015 00:51:37
Copyright (c) 1997, 2005, Oracle. All rights reserved.
Used parameter files:
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST =
172.101.19.57)(PORT = 1521))) (CONNECT_DATA = (service_name = dcsopen)))
TNS-12560: TNS:protocol adapter error
执行sqlplus ...@dcsopen报错：
SQL*Plus: Release 10.2.0.1.0 - Production on Thu Jan 8 00:58:14 2015
Copyright (c) 1982, 2005, Oracle. All rights reserved.
ERROR:
ORA-12560: TNS:protocol adapter error
于是先看看端口是否开通，执行telnet报错：
ora10g@localhost.localdomain$telnet
172.101.19.57 1521
Trying 172.101.19.57...
telnet: connect to address
172.101.19.57: No route to host
如果端口未开，实际报错：
ora10g@localhost.localdomain$telnet 172.27.19.56 1521
Trying 172.27.19.56...
telnet: connect to address 172.27.19.56: Connection refused
是不是防火墙的问题？？？
从数据库服务器关闭防火墙：
[root@dcsopen2Node ~]# service iptables stop
iptables: Flushing firewall rules: [ OK ]
iptables: Setting chains to policy ACCEPT: nat mangle filter [ OK ]
iptables: Unloading modules: [ OK ]
再从远程机器执行：
ora10g@localhost.localdomain$telnet
172.101.19.571521
Trying 172.101.19.57...
Connected to 172.101.19.57.
Escape character is '^]'.
说明端口已开，更重要的是，明确了，就是防火墙问题。于是参考，将/etc/sysconfig/iptables文件新增一行，表示允许1521端口访问：
[root@dcsopen2Node sysconfig]# vi iptables
# Firewall configuration written by system-config-firewall
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 1521 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT
启动防火墙：
[root@dcsopen2Node sysconfig]# service iptables start
iptables: Applying firewall rules: [ OK ]
或service iptables restart
从远程机访问：
ora10g@localhost.localdomain$sqlplus dcsopen/dcsopen1@dcsopen
SQL*Plus: Release 10.2.0.1.0 - Production on Thu Jan 8 01:11:12 2015
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
正常了。
总结：
1. listener.ora和tnsnames.ora配置文件最好使用netca工具创建，否则手工修改很可能出现各式问题导致无法解析读取。
2. 我的排查思路是，先确保本机可以tnsping和sqlplus ...@xxx，本机可访问了，再看远程机器。
远程访问tnsping和sqlplus报错TNS-12560: TNS:protocol adapter error，说明可能两台机器之间的连接有问题而不是监听自身的问题。
3. telnet报错是No route to host，不是Connection refused，不可轻易认为是网络端口未开。因为此时表示可以正常访问到另一台远程机器了，应该考虑到是否是防火墙的问题。此时可以通过关闭防火墙测试是否会出现这个问题来判断。
4. 会使用tnsping的trace跟踪，设置sqlnet.ora配置文件。
5. 动态注册的使用。好处：简化监听器配置、连接时failover(RAC)、运行时负载均衡(RAC)。
6. 解决过程中，有的帖子说需要设置$TNS_ADMIN环境变量，尽管这是有两个Oracle版本同机，但后来测试不配置，也可以访问，说明这不是关键问题。
解决过程中，有的帖子说sqlnet.ora中的NAME.DEFAULT_DOMAIN参数，以为从跟踪日志tnsping.trc看default name server domain is [root]，可后来没有设置，也可以访问，说明这不是关键问题。
解决过程中，对我有帮助的帖子：
http://blog.itpub.net/7199859/viewspace-374281/
http://blog.itpub.net/519536/viewspace-673794/
http://blog.sina.com.cn/s/blog_9151e7300101ksui.html
http://www.cnblogs.com/chinaairforce1/archive/2009/10/22/1588103.html
http://blog.csdn.net/huzia/article/details/21526043
7.
最重要的一条总结：不放弃！
辅助知识：
执行netca前需要root执行xhost +，否则提示：
java.lang.NullPointerException
at oracle.ewt.lwAWT.BufferedApplet.<init>(Unknown Source)
at oracle.net.ca.NetCA.<init>(NetCA.java:420)
at oracle.net.ca.NetCA.main(NetCA.java:406)
仍存问题：
对比如下配置，未发现不同点，奇怪：
手工创建：
dcsopen =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 172.101.19.57)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = dcsopen)
)
)
工具创建：
DCSOPEN =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST =
172.101.19.57)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = dcsopen)
)
)