centos - Make Apache server only accept requests to domain rather than IP

I have a CentOS server running Apache 2.2.15. If the IP address of the server is 198.51.100.4 and I write in browser http://198.51.100.4 it goes on my website.

I want to prevent this. I want my website to be accessible only on the FQDN i.e. http://example.com/.

How can I configure my server so the website is not accessible when I visit the IP address?

Answer

You can use Alias * to catch any other trafic than thoose allowed in your virtual host, for this you have to use in the last position a virtual host with * as alias.

Like that only defined domain will be served.

ServerName mywebsite.com

DocumentRoot /var/www/default
...



ServerName another.mywebsite.com
DocumentRoot /var/www/another
...



# /!\ THIS HAS TO BE ON THE LAST POSITION /!\

# [ Server Domain ]
ServerName localhost
ServerAlias *
# [ Cancel trafic ]
RewriteRule .* - [END,R=406]
# [ Custom Log ]
CustomLog ${APACHE_LOG_DIR}/other.log combined

In my example only mywebsite.com & another.mywebsite.com will be allowed, all other domains or IP will have trafic cancelled.

To cancel the trafic you can use a redirect to - and then add an error code, for example i used a RewriteRule to redirect to 406 Not Acceptable (R=406).

Here you can find the list of redirect codes:
https://fr.wikipedia.org/wiki/Liste_des_codes_HTTP