One or more conditions given in the request header fields evaluated to false when tested on the server.
This response code allows the client to place preconditions on the current resource state (its current representations and metadata) and, thus, prevent the request method from being applied if the target resource is in an unexpected state.
The target resource does not have a current representation that would be acceptable to the user agent, according to the proactive negotiation header fields received in the request, and the server is unwilling to supply a default representation. The server SHOULD generate a payload containing a list of available representation characteristics and corresponding resource identifiers…
The 7 layers of the OSI model describe how computer systems communicate over a network. Understanding the functions and responsibilities of each layer will help you understand how network communications function. The development of the OSI model started in the late 1970s to support the emergence of diverse computer networking methods, such as the current…
Any attempt to brew coffee with a teapot should result in the error code “418 I’m a teapot”. The resulting entity body MAY be short and stout.
This status code is not specified in any RFCs, but is used by some HTTP proxies to signal a network connect timeout behind the proxy to a client in front of the proxy.
The client needs to authenticate to gain network access. The response representation SHOULD contain a link to a resource that allows the user to submit credentials (e.g., with an HTML form). Note that the 511 response SHOULD NOT contain a challenge or the login interface itself, because browsers would show the login interface as being…
Defined in a previous version of this specification and is now deprecated, due to security concerns regarding in-band configuration of a proxy.