HTTP Status Codes - Part 3 of Chapter 3 from HTTP: The Definitive Guide (5/6)

Sometimes a client sends something that a server just can't handle, such as a badly formed request message or, most often, a request for a URL that does not exist.

We've all seen the infamous 404 Not Found error code while browsing--this is just the server telling us that we have requested a resource about which it knows nothing.

Many of the client errors are dealt with by your browser, without it ever bothering you. A few, like 404, might still pass through. Table 3-9 shows the various client error status codes.