how to modify Apache to Allow URL Rewrites?

root@change:~# ls /etc/apache2/sites-available/ default default-ssl

root@change:~# cat /etc/apache2/sites-available/default <VirtualHost *:80> ServerAdmin webmaster@localhost

    DocumentRoot /var/www
    <Directory />
            Options FollowSymLinks
            AllowOverride None
    </Directory>
    <Directory /var/www/>
            Options Indexes FollowSymLinks MultiViews
            AllowOverride None
            Order allow,deny
            allow from all
    </Directory>

    ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
    <Directory "/usr/lib/cgi-bin">
            AllowOverride None
            Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
            Order allow,deny
            Allow from all
    </Directory>

    ErrorLog ${APACHE_LOG_DIR}/error.log

    # Possible values include: debug, info, notice, warn, error, crit,
    # alert, emerg.
    LogLevel warn

    CustomLog ${APACHE_LOG_DIR}/access.log combined

</VirtualHost>

I have tested to change “AllowOverride None” into “AllowOverride All” in the file " /etc/apache2/sites-available/default" and set permalinks in wordpress setting to post name and input the command : sudo a2enmod rewrite sudo service apache2 restart

done!

There is the last problem remain here: What is the different betwwen them : /etc/apache2/sites-available/default and /etc/apache2/sites-available/default-ssl?