The following is a shortlist of common redirects. You may not be able to implement all of the redirects but you may also have run into a few of them and its always a good idea to recognize them and know what they mean. So here they are:
Http 301 – the 301 code means that the URL you are requested, meaning, the website you are attempting to visit, has been permanently moved. This is usually used to avoid duplicate content issues when similar documents are located on different URLs.
Http 302 – This means the document you are searching for has been temporarily moved to a different location.
Http 400 – This code means that there was most likely a syntax error in the URL entered and as a result the server is unable to understand your document request.
Http 401 – This means that there has been an unauthorized request and that the server requires authentication before carrying out the document request.
Http 403 – The server has understood the request but it refuses to fulfill it. This is a ‘forbidden’ code response. A webmaster may alert the user as to the reason his request is being denied, but if he prefers not to notify users, he may use a 404 status code instead.
Http 404 – This response means in general that the document you requested cannot be found. The client was able to communicate with the server but the server was not able to find the requested document. This could also mean that the server was told to refuse the request without providing a reason.
Http 410 – Similar to a 404, the 410 code indicates that the document you requested is ‘intentionally gone’ and will no longer be available at this URL address, while there is also no forwarded address. This code is usually used for documents such as promotional information and it is up to the webmaster and at his discretion to determine when to remove the 410 status code.
Http 500 – This indicates an internal server error that is preventing the document from loading.
Http 501 – This indicates that the server does not recognize the document request method. Since the server cannot fulfill the request it displays a ‘not implemented’ status code.
This sums up the basic redirects and what they mean. Just remember that redirects are often problematic and collide with good SEO. This is because good SEO will always prefer to have the simplest and fastest access to a website, for the best usability. Redirects complicate things so don’t use them unless you absolutely have to.