A look at HTTP Status Codes - Server Headers

HTTP Protocol is a different subject altogether. Lets get some glimpse of what HTTP status codes or Server headers are and how are they useful for search engine optimization. When a client or a customer is making a request to a web server through a web browser, the request goes to the web server and HTTP status codes are returned in the header of the web server response. The client decides on what action to be taken.

For Example if the client receives the status code 200, Which is ok, it means that the webpage is found and is returned in the browser.

Lets look at the different status codes that are available. From the Search engine marketing or optimization point of view there are 11 major status codes that you need to know 200, 301, 302, 304, 307, 400, 401, 403, 404, 500 and 501.

1. 200 - OK : as discussed earlier 200 is a "OK". That means that request has been successful.

2. 301 - Moved Permanently: This means that the request is assigned or directed to new URL and will have a permanent redirection.

3. 302 - Found: The requested resource resides temporarily under a different URI. Since the redirection might be altered on occasion, the client SHOULD continue to use the Request-URI for future requests. This response is only cacheable if indicated by a Cache-Control or Expires header field.

4. 304 Not Modified: If the client has performed a conditional GET request and access is allowed, but the document has not been modified, the server SHOULD respond with this status code. The 304 response MUST NOT contain a message-body, and thus is always terminated by the first empty line after the header fields.

5. 307 Temporary redirection: It means the URL request that is made from the client is temporally in a different URL. From My personal experience I would recommend that don't use temporary redirection for the web pages that you are optimizing, unless it is really genuine. If you see that the web page is moved permanently use 301 instead.

6. 400 Bad Request: If the web server does not understand the request, it gives a 400 error. It is always recommended that you give the same request without any modifications.

7. 401 Unauthorized: This code will appear if the client requires any authentication to perform for proceeding further.

8. 403 Forbidden : this status normally happens when the internet connection is down or slow or the web server has understood the request and is not performing the function due to various reasons like as I mentioned about you internet connection or if the server is over loaded etc.

9. 404 - Not Found: We usually keep seeing this status with many web pages. This means that the page that the client has requested is not found.

10 Internal Server Error: If the server encountered any problem and temporarily is not fulfilling on the request made.

11. 501 Not Implemented: This status generally comes when the server is not capable of recognizing the request made or even is not capable of returning response to the request made.


For Further reference, see links below:

Website Technology Issues

W3C Status Codes