oracle@m1:~$ lsnrctl start

LSNRCTL for Linux: Version 11.1.0.6.0 - Production on 15-APR-2008 19:30:14

Copyright (c) 1991, 2007, Oracle.  All rights reserved.

Starting /mnt/oracle/app/oracle/product/11.1.0/db_1//bin/tnslsnr: please wait...

TNSLSNR for Linux: Version 11.1.0.6.0 - Production
System parameter file is /mnt/oracle/app/oracle/product/11.1.0/db_1/network/admin/listener.ora
Log messages written to /mnt/oracle/app/oracle/product/11.1.0/db_1/log/diag/tnslsnr/m1/listener/alert/log.xml
Error listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1521)))
TNS-12555: TNS:permission denied
 TNS-12560: TNS:protocol adapter error
  TNS-00525: Insufficient privilege for operation
   Linux Error: 1: Operation not permitted

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

oracle@m1:~$