CNStats 3.2 Manual
The report displays the number of viewings of pages which have not been found.
The principle of the report's functioning is equal to "Popular pages" report.
One should set a counter code for "404" pages at "404" page for correct display of the report. The counter code can be obtained at "Configuration - Counter code".
The web-server generates an error "404" and passes it to the client. Beside the response code "404", which is transferred in the header of HTTP response, the web-server passes over a standard page, containing the error text. The browser displays this page.
Upon using Apache web-server you can create your own "404" page with the help of ErrorDocument command.
Note: Microsoft Internet Explorer replaces "404" page, obtained from the server, to its own page in case the page length does not exceed 512 bytes. Therefore, for correct display of "404" page, its size should be greater than 512 bytes.