HTTP 411 Length Required vs 510 Not Extended
HTTP 411 (Length Required) is a 4xx Client Error response, while 510 (Not Extended) is a 5xx Server Error response. 411 indicates that the server refuses to accept the request without a Content-Length header. In contrast, 510 means that further extensions to the request are required for the server to fulfill it.
Description
The server refuses to accept the request without a Content-Length header.
When You See It
When sending a request body without specifying Content-Length.
How to Fix
Include a Content-Length header in your request.
Description
Further extensions to the request are required for the server to fulfill it.
When You See It
When an HTTP extension required by the server is not present in the request.
How to Fix
Add the required extension headers to your request.
Key Differences
411 is a 4xx Client Error response, while 510 is a 5xx Server Error response.
HTTP 411: The server refuses to accept the request without a Content-Length header.
HTTP 510: Further extensions to the request are required for the server to fulfill it.
You encounter 411 when when sending a request body without specifying Content-Length.
You encounter 510 when when an HTTP extension required by the server is not present in the request.
When to Use Which
For 411 (Length Required): Include a Content-Length header in your request. For 510 (Not Extended): Add the required extension headers to your request.