Tns-12541:tns:no Listener, tns-12542:tns:address already in use

View database listening status is incorrect
$ LSNRCTL Status

Lsnrctl for Ibm/aix RISC system/6000:version 10.2.0.5.0-production on 05-nov-2012 08:54:08

Copyright (c) 1991, Oracle. All rights reserved.

Connecting to (Description= (address= (protocol=tcp) (host=test) (port=1521)))
Tns-12541:tns:no Listener
Tns-12560:tns:protocol Adapter Error
Tns-00511:no Listener
Ibm/aix RISC system/6000 Error:79:connection refused
Then manually start the database to report the following error:
$ lsnrctl Start

Lsnrctl for Ibm/aix RISC system/6000:version 10.2.0.5.0-production on 05-nov-2012 08:54:12

Copyright (c) 1991, Oracle. All rights reserved.

Starting/oracle/product/10.2.0/db_1/bin/tnslsnr:please wait ...

Tnslsnr for Ibm/aix RISC system/6000:version 10.2.0.5.0-production
System parameter File Is/oracle/product/10.2.0/db_1/network/admin/listener.ora
Log messages Written To/oracle/product/10.2.0/db_1/network/log/listener.log
Error listening on: (Description= (Address= (protocol=tcp) (host=test) (port=1521)))
Tns-12542:tns:address already in use
Tns-12560:tns:protocol Adapter Error
Tns-00512:address already in use
Ibm/aix RISC system/6000 error:67:address already in use

Listener failed to start. See the error message (s) above ...

/oracle/product/10.2.0/db_1/network/trace/listener.trc

Obviously monitoring did not start, but said already in operation, and then finally found the reason, on-line to see other people also encounter this problem, said is the Hosts file setup problem, check the host name and Hosts file, there is a problem, two IP address point to the same host name, a host deleted, then start monitoring, Everything OK.

To modify with the root user:
# cat/etc/hosts

# Internet Address Hostname # Comments
# 192.9.200.1 Net0sample # Ethernet Name/address
# 128.100.0.1 Token0sample # Token Ring name/address
# 10.2.0.2 X25sample # x. name/address
# 2000:1:1:1:209:6bff:feee:2b7f Ipv6sample # ipv6 name/address
127.0.0.1 loopback localhost # loopback (lo0) name/address
192.168.101.189 Test
192.168.101.190 Test

Start monitoring again:
$ lsnrctl Start

Lsnrctl for Ibm/aix RISC system/6000:version 10.2.0.5.0-production on 05-nov-2012 08:58:47
Copyright (c) 1991, Oracle. All rights reserved.

Starting/oracle/product/10.2.0/db_1/bin/tnslsnr:please wait ...

Tnslsnr for Ibm/aix RISC system/6000:version 10.2.0.5.0-production
System parameter File Is/oracle/product/10.2.0/db_1/network/admin/listener.ora
Log messages Written To/oracle/product/10.2.0/db_1/network/log/listener.log
Listening on: (Description= (Address= (protocol=tcp) (host=test) (port=1521)))
Listening on: (Description= (Address= (PROTOCOL=IPC) (KEY=EXTPROC0)))

Connecting to (Description= (address= (protocol=tcp) (host=test) (port=1521)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version Tnslsnr for Ibm/aix RISC system/6000:version 10.2.0.5.0-production
Start Date 05-nov-2012 08:58:49
Uptime 0 days 0 hr. 0 min. 0 sec
Trace level off
Security on:local OS Authentication
SNMP on
Listener Parameter File/oracle/product/10.2.0/db_1/network/admin/listener.ora
Listener Log File/oracle/product/10.2.0/db_1/network/log/listener.log
Listening Endpoints Summary ...
(Description= (address= (protocol=tcp) (host=test) (port=1521)))
(Description= (address= (PROTOCOL=IPC) (KEY=EXTPROC0)))
Services Summary ...
Service "Plsextproc" has 1 instance (s).
Instance "Plsextproc", status UNKNOWN, have 1 handler (s) for the This service ...
The command completed successfully

Summary :/etc/hosts file Settings is very important, here is not set correctly, many places have to make mistakes, especially RAC, will report a lot of strange errors, configure the time to pay more attention.

REF:

Http://www.linuxidc.com/Linux/2012-11/73694.htm

Http://www.xifenfei.com/2152.html

Tns-12541:tns:no Listener, tns-12542:tns:address already in use