Modifying your error pages.

The location of the error pages is

/var/www/error

Editing the files in that directory enables you to have custom error pages, noindex pages, 404 pages etc.

You can customise them to suit your sites look and feel, or even add extra functionality if desired.

Note, the above location may vary on different servers - the location given is where they are on my goddady centos vps. You will need to do your own research to find the exact location if you are not there!