What is a 404 not found template?
Whenever the website visitor requests a page that doesn't – or no longer – exists, the 404 not found template is reserved by the web server. A 404 template was created in order to simplify and ease the error handling procedure. The web server no longer has to search for the file, but informs the visitor that the file cannot be found.
A 404 template is generally a white page with a short text in black letters stating "page not found". It is however also possible to design a 404 template so the page is presented to the visitor in the same style and color of the website.
It’s also possible that the page has been listed by the search engines, and therefore visitors land on a dead page. Search engine web crawlers are usually aware of this and they will remove the page from their index whenever it gives them a 404 error.
Not found pages are generally stored in the web server log. The webmaster of the website is responsible for regularly monitoring this log and following up on incidents. The log usually also includes the referring link (the website that referred the visitor), allowing the webmaster to repair the referring links to the dead pages.