title: Oracle TNS listener not starting on CentOS 7
body: <p>I have installed Oracle 11g Release 2 Express edition on CentOS 7 machine. The installation process is completed successfully saying below.</p>
  
  <pre><code>Starting Oracle Net Listener...Done
  Configuring database...Done
  Starting Oracle Database 11g Express Edition instance...Done
  Installation completed successfully.
  </code></pre>
  
  <p>When I do tnsping to the service I am getting below error.</p>
  
  <pre><code>Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = i2b2)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = XE)))
  TNS-12541: TNS:no listener
  </code></pre>
  
  <p>I then tried to start the listener and it's failing with below error.</p>
  
  <pre><code>TNSLSNR for Linux: Version 11.2.0.2.0 - Production
  NL-00280: error creating log stream /u01/app/oracle/product/11.2.0/xe/network/log/listener.log
   NL-00278: cannot open log file
    SNL-00016: snlfohd: error opening file
     Linux Error: 13: Permission denied
  </code></pre>
  
  <p>I searched a lot on forums and tried the given solutions there but could not solve the issue. What can be the issue in this case ?</p>
  
  <p>Any help is really appreciated.</p>
  
  <p>Edit:</p>
  
  <p>Here is my tnsnames.ora file.</p>
  
  <pre><code>XE =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = i2b2)(PORT = 1521))
      (CONNECT_DATA =
        (SERVER = DEDICATED)
        (SERVICE_NAME = XE)
      )
    )
  
  EXTPROC_CONNECTION_DATA =
    (DESCRIPTION =
      (ADDRESS_LIST =
        (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC_FOR_XE))
      )
      (CONNECT_DATA =
        (SID = PLSExtProc)
        (PRESENTATION = RO)
      )
    )
  </code></pre>
  
  <p>And listener.ora file.</p>
  
  <pre><code>SID_LIST_LISTENER =
    (SID_LIST =
      (SID_DESC =
        (SID_NAME = PLSExtProc)
        (ORACLE_HOME = /u01/app/oracle/product/11.2.0/xe)
        (PROGRAM = extproc)
      )
    )
  
  LISTENER =
    (DESCRIPTION_LIST =
      (DESCRIPTION =
        (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC_FOR_XE))
        (ADDRESS = (PROTOCOL = TCP)(HOST = i2b2)(PORT = 1521))
      )
    )
  
  DEFAULT_SERVICE_LISTENER = (XE)
  </code></pre>
  
  <p>Environmental variables:</p>
  
  <pre><code>ORACLE_HOME=/u01/app/oracle/product/11.2.0/xe
  export ORACLE_HOME
  
  ORACLE_SID=XE
  export ORACLE_SID
  
  export TNS_ADMIN=/u01/app/oracle/product/11.2.0/xe/network/admin
  export NLS_LANG=`$ORACLE_HOME/bin/nls_lang.sh`
  
  JAVA_HOME=/usr/java/jdk1.7.0_65
  export JAVA_HOME
  
  PATH=$PATH:$HOME/bin:$ORACLE_HOME/bin:/usr/local/apache-ant-1.8.4/bin:$JAVA_HOME/bin
  
  export PATH
  </code></pre>