200 Status OK
A message that is displayed on a browser when a file or page is located properly. Although rare, it is possible to see this message even when a file does not exist. The correct response should instead be a 404 error.
301 Redirect
A website status code that informs a search engine robot that a page has permanently moved. 301 redirects may be set within certain page types, via a .htaccess file, or even by the web server application itself. A 301 redirect on a page passes along to the new page at least some of the benefits of links to the old page.
302 Redirect
A website status code that informs a search engine robot that a page has temporarily moved. 302 redirects may be set via various methods depending upon one’s web server platform.
403 Error Message
Prevents user access to a particular URL and states the reason why that access has been denied. Usually because the user does not have the authority to view the content. Also known as a “forbidden” message.
404 Error
A HTTP error returned by a web server to a browser when the requested web page is not available.
