Once configured and restarting successfully on Apache. just it is not sure where you need serve from, so it's choosing your localhost ​(127.0.0.1) by default. To avoid this message, that you want to serve from localhost (127.0.0.1), just the below line in Apache configure file.



* Restarting web server apache2                                                                                                                      

 AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.30.1.16. Set the 'ServerName' directive globally to suppress this message  [ OK ]


Open the configure file and appand a line,


#  vim /etc/apache2/apache2.conf



ServerName localhost


Finally, restart the Apache service.

# service apache2 restart