TNS-00507: Connection closed Linux Error: 29: Illegal seek

 FIX TNS:Connection closed error?

I got an email from users saying they are unable to connect to one of the DEVELOPMENT server. They are getting “NO LISTENER” message. So, its clear from this that listener could have been shutdown.
I logged in and checked the listener status using both “lsnrctl status” command and “ps -ef | grep tns” command. Both of the commands didn’t given any posivitive result.
So I started the listener with the below command and got error as this…
[oracle@dbserver1 admin]$ lsnrctl start LISTENER


LSNRCTL for Linux: Version 10.2.0.1.0 – Production on 25-APR-2012 18:16:24

Copyright (c) 1991, 2005, Oracle.  All rights reserved.

Starting /u01/ora10g/bin/tnslsnr: please wait…

TNS-12537: TNS:connection closed
 TNS-12560: TNS:protocol adapter error
  TNS-00507: Connection closed
   Linux Error: 29: Illegal seek

The problem is identified as a line is missing in /etc/hosts file (mine is a Linux server). I added below line and problem solved

127.0.0.1         localhost.localdomain       localhost

So, whenever you hit with the above error (Illegal Seek), please check hosts file and add the above line which will solve the issue……