DB Listener failed to start with TNS-12555: TNS:permission denied Error

Oracle Net Services - Version: 10.2.0.1.0 to 11.1.0.7.0 - Release: 10.2 to 11.1
Information in this document applies to any platform.
This issue could present on any UNIX platform.

Checked for relevance on 30-SEP-2011.
Symptoms

An attempt to start the Listener using lsnrctl start yields any of the error stacks below:

TNS-12555: TNS:permission denied
TNS-12560: TNS:protocol adapter error
TNS-00525: Insufficient privilege for operation
Linux Error: 1: Operation not permitted

TNS-12560: TNS:protocol adapter error
TNS-00530: Protocol adapter error
HPUX Error: 20: Not a directory

TNS-12557: TNS: Protocol adapter not loadable
TNS-12560: TNS: Protocol adapter error
TNS-00527: Protocol Adapter not loadable


TNS-12555: TNS:permission denied
TNS-12560: TNS:proto adapter error
TNS-00525: Insufficient privilege for operation
IBM/AIX RISC System/6000 Error: 1: Not owner
Using only the IPC protocol in the listener.ora and a level 16 listener trace reveals the following:

Changes
This is either a new installation or some permissions changes have taken place on the /.../.oracle directory.
Cause

1) Ensure that /tmp/.oracle or /var/tmp/.oracle directory exists.

2) Confirm that the user who is trying to start the listener has adequate read and write permissions on the directory specified above. The permissions should be 777.

3) If the /tmp directory has reached full capacity, this would cause the listener to fail to write the socket files.

Solution
To implement the solution, please use the following example:

1. cd /var/tmp

2. Check the whether the .oracle directory exists:

$cd .oracle

3. If the directory does not exist, request the System Administrator create the directory and set the ownership as root:root with the permissions set to 01777

#mkdir /var/tmp/.oracle
#chmod 01777 /var/tmp/.oracle
#chown root /var/tmp/.oracle
#chgrp root /var/tmp/.oracle

4. Next try starting the TNS Listener using the ‘lsnrctl start <listener_name>’ command.