Oracle XE 11g Post Installation Issue

After installing Oracle XE 11g database, if you get below error when running below command,

[root@*** ~]# /etc/init.d/oracle-xe status

LSNRCTL for Linux: Version 11.2.0.2.0 - Beta on 19-APR-2011 04:07:41

Copyright (c) 1991, 2010, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC_FOR_XE)))
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=*******)(PORT=1521)))
TNS-12541: TNS:no listener
TNS-12560: TNS:protocol adapter error
 TNS-00511: No listener
  Linux Error: 111: Connection refused

then it is an issue with network settings of your OS. The main reason is that the listener.ora was referencing a network settings which was modified after the Oracle XE installation.

The solution is to rename the listener.ora to something different (for example, listener.ora_old) and then restart the database by /etc/init.d/oracle-xe restart