apache2: Could not reliably determine the server's fully qualified domain name

Question

I've never encountered this error before. And secondly I'd like to know how you folks debug your apache configurations.

apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1 for ServerName

In my Virtual Host configuration I do have these lines:

ServerName  example.com
ServerAlias www.example.com

(of course it has my actual info in there)

So I guess my question is, why wouldn’t apache be able to determine my fully qualified domain name?

Answer 1

check your /etc/hosts file. It should look something like this:

127.0.0.1     localhost
a.b.c.d       www.example.com

The first line should already be there, you only have to add the second line with your values.

Answer 2

I think it's because you need to have "ServerName" declared outside vhost configuration, in the apache2.conf and the ServerName value declared in the /etc/hosts