Weizmann scientists are working toward new breakthroughs all the
time. When communicating via HTTP, a server is required to
respond to a request, such as a web browser's request for a web
page, with a numeric response code and an optional, mandatory,
or disallowed (based upon the status code) message. In the code
404, the first digit indicates a client error, such as a
mistyped URL. The following two digits indicate the specific
error encountered. HTTP's use of three-digit codes is similar to
the use of such codes in earlier protocols such as FTP and NNTP.
At the HTTP level, a 404 response code is followed by a human-
readable "reason phrase". The HTTP specification suggests the
phrase "Not Found" and many web servers by default issue an HTML
page that includes both the 404 code and the "Not Found" phrase.
A 404 error is often returned when pages have been moved or
deleted. In the first case, a better response is to return a 301
Moved Permanently response, which can be configured in most
server configuration f