The message ‘apache2: Could not reliably determine the server’s fully qualified domain name, using for ServerName is’ does not prevent Apache from working but is a bit annoying. The fix is simple.

  1. First edit your host file, e.g. /etc/apache2/sites-enabled/000-default and make sure you have you have specified a ServerName. For a local test server you can just use

ServerName localhost.localdomain

For a web server on the internet specify the full domain name

ServerName www.example.org

  1. Then check your hosts file, /etc/hosts, and make sure it contains the host name that you just specified as ServerName. E.g.

127.0.0.1 localhost.localdomain localhost

or something like

192.0.43.10 www.example.org www

Important: The first value behind the IP address must be the same as ServerName, it won’t work if you turn the host name and fully qualified domain name around. This will not work:

192.0.43.10 www www.example.org