Mediawiki 403 forbidden errors after upgrading to Ubuntu 13.10

  A customer upgraded from 13.04 to 13.10 and their internal wiki was broken afterwards; for a simple Apache install where the wiki was installed at the web root and all access was via the LAN (thus they were happy with not restricting the access), the fix was to add:  
<Location /> Require all granted </Location>
  towards the bottom of:  
/etc/apache2/sites-enabled/000-default.conf  
…just above the last line, which should be </VirtualHost>. Restart apache with:  
service apache2 restart
  After that you should be able to refresh and see your wiki as before.

New CentOS WordPress install: Error 500

  Was asked to troubleshoot a client’s installation technique for WordPress on CentOS 6.x yesterday; they were receiving an Error 500 when they tried to access index.php for the first time. Checking the Apache logs showed:  
SoftException in Application.cpp:431: Mismatch between target GID (522) and GID (65531) of file “/home/andrea/public_html/index.php” Premature end of script headers: index.php
  What was happening was that the client was un-tarballing the latest.tar.gz file as root and then changing the ownership of the file with the following:  
chown -R [user] *
  Changing that command to:  
chown -R [user]:[usergroup] *  
e.g. here:  
chown -R andrea:andrea *
  fixed that error. By not specifying the new group there was an ownership mismatch where the system expected one group but got another. There are many¬† causes for an Error 500 – it’s a good habit to check the Apache logs first for pointers as to where to start troubleshooting.