在ORACLE测试服务器上还原恢复了一个数据库后，启动监听服务时出现了TNS-12541, TNS-12560,TNS-00511之类的错误，具体情况如下所示：
[oracle@getlnx01 admin]$ lsnrctl status
LSNRCTL for Linux: Version 10.2.0.4.0 - Production on 09-MAR-2015 09:13:29
Copyright (c) 1991, 2007, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1)))
TNS-12541: TNS:no listener
TNS-12560: TNS:protocol adapter error
TNS-00511: No listener
Linux Error: 111: Connection refused
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=getlnx01.esqule.com)(PORT=1521)))
TNS-12541: TNS:no listener
TNS-12560: TNS:protocol adapter error
TNS-00511: No listener
Linux Error: 111: Connection refused
[oracle@getlnx01 dbs]$ lsnrctl start
LSNRCTL for Linux: Version 10.2.0.4.0 - Production on 09-MAR-2015 09:20:46
Copyright (c) 1991, 2007, Oracle. All rights reserved.
Starting /u01/app/oracle/product/10.2.0/db_1/bin/tnslsnr: please wait...
TNSLSNR for Linux: Version 10.2.0.4.0 - Production
System parameter file is /u01/app/oracle/product/10.2.0/db_1/network/admin/listener.ora
Log messages written to /u01/app/oracle/product/10.2.0/db_1/network/log/listener.log
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1)))
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=getlnx01.esqule.com)(PORT=1521)))
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1)))
TNS-12547: TNS:lost contact
TNS-12560: TNS:protocol adapter error
TNS-00517: Lost contact
Linux Error: 104: Connection reset by peer
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=getlnx01.esqule.com)(PORT=1521)))
TNS-12541: TNS:no listener
TNS-12560: TNS:protocol adapter error
TNS-00511: No listener
Linux Error: 111: Connection refused
因为曾经遇到并解决过TNS-12541这类错误，立即检查/etc/hosts文件，结果发现IP地址写错了，正确的IP地址应该为192.168.7.221,而不是粗心手误写错的192.168.7.211
[root@getlnx01 ~]# more /etc/hosts
# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1 getlnx01.esqule.com getlnx01
192.168.7.211 getlnx01.esqule.com getlnx01
修改为正确的IP地址后，依然出现这个错误，后面查看了官方文档Starting TNS Listener or LSNRCTL Start Yields TNS-12541, Linux Error: 111: Connection Refused (文档 ID 343295.1)后，才发现是因为本地主机环回名称和地址不正确所致，修改/etc/hosts后，重启监听服务，问题解决。
[oracle@getlnx01 ~]$ more /etc/hosts
# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1 localhost.localdomain localhost
192.168.7.221 getlnx01.esqule.com getlnx01
CAUSE
1. There is possibly an incorrect IP Address specified for the host in the /etc/hosts file.
For example:
192.168.101.101 prod1.us.oracle.com prod1
Whereas the actual ip address for the host "prod1.us.oracle.com" is 192.168.101.110
2. Also, the localhost reference may be incorrect or missing from the /etc/hosts file.
3. Oracle may not have read access to /etc/nsswitch.conf file.
SOLUTION
To implement the solution, please execute the following steps:
1. Correct the mapping in the /etc/hosts file by adding/correcting the IP address and/or hostname reference for the Unix/Linux Server (both long and short host names).
For example:
# Add or edit the /etc/hosts file to include a valid entry for the Server:
192.168.101.110 prod1.us.oracle.com prod1
2. Check that the localhost loopback name and address are correct (both long and short host names).
An example of a correct localhost entry would be as follows:
127.0.0.1 localhost.localdomain localhost
3. Remember to save the /etc/hosts file and then start the listener.
4. Check permissions on /etc/nsswitch.conf file to ensure group and other have read access.
- If necessary change permisions on /etc/nsswitch.conf as follows:
chmod 644 /etc/nsswitch.conf
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