HTTP Response Codes

HTTP defines forty standard status codes that can be used to convey the results of a client’s request. The status codes are divided into the five categories presented below.

CATEGORY	DESCRIPTION
1xx: Informational	Indicates that the client's request is being processed.
2xx: Success	Indicates that the client’s request was accepted successfully.
3xx: Redirection	Indicates that the client must take some additional action in order to complete their request.
4xx: Client Error	Indicates an error for which the client is responsible.
5xx: Server Error	Indicates an error for which the server is responsible.

Below are examples of the most common HTTP codes you will encounter in the logs:

HTTP Code	Description
200	OK: the standard response for successful HTTP requests.
301	Used for URL redirection
400	Bad Request
401	Unauthorized—authentication has failed
403	Forbidden—request refused by Link11 or origin server
404	Destination not found
405	Method not allowed
408	Request timeout
413	Payload too large
414	Request-URI too long
444	No Response (nginx)
499	Client Closed Request (nginx)
500	Internal Server Error
503	Service Unavailable—Server is unable to handle the request
505	HTTP version not supported