404 not found page

404 is a Hypertext Transfer Protocol status code. Hypertext Transfer Protocol is the protocol web servers use to communicate with web browsers. When you type in a URL to try to visit a web page, your computer sends a request message to the server and the server sends back the HTTP header to your browser, which includes a status message before you even see the web page. Normally, if everything is correct, the status code is “200 OK”, but you don’t see it because you see the page you were looking for. But if the server cannot find the page you are looking for, it reports the status as “404 Not Found”.

The numbers 4-0-4 each actually mean something as individual digits. The first 4 is telling you, the client, that there is a mistake on your end, such as a possibly mistyped URL or a request for a page that no longer exists. The 0 just represents a syntax error- it basically just means “something isn’t right”. Now after the 4-0, the last number could be any one of several digits that indicates the type of error. The 4 in that section means that the page cannot be located. Another status messages could be 401, which means you are unauthorized to view that page. 

There is a clever myth behind the 404 Not Found message. The story goes that 404 was the room number of the room where the very first web servers were located. But there story includes a mystery- there is no room 404 in that building at CERN, where the first web servers were held. So the 404 Not Found code is a bit of an inside joke for those who have heard the story.

You can use your log files to spot “404s” by reviewing the logs of your status codes. Take note any of 404 occurrences. If there seem to be quite a few, more than you could chalk up to user error, you might have a broken link in there somewhere. Check the referring page, the page the user was at just before arriving that the 404, then inspect that page to find the broken link and fix it. If you do not have access to your log files, you can request them from your website host.

The 404 Not Found Page comes up on your screen for several different reasons:

The page may have been moved. In this case, it is as though you are trying to visit a friend when you find a note taped to their door that says they have moved. But it doesn’t tell you where they moved to. Not very helpful, is it? The 404 Not Found page is a note like that.

The hyperlink you followed my have a minor error in the URL.

The page may simply be gone. Not moved. Just taken down. And whatever linked you to it doesn’t know it. This is a form of Linkrot.