HTTP 511 Network Authentication Required

Overview

The HTTP 511 Network Authentication Required status code is used to indicate that the client needs to authenticate to gain network access.

Purpose

The HTTP 511 response is utilized to inform the client that network access is denied and requires authentication.

Usage

Client Behavior:

1. Access Resource: The client attempts to access a resource that requires network authentication.
2. Receive Response: The client receives an HTTP 511 status code indicating the need for network authentication.

Server Behavior:

1. Network Authentication Required: The server identifies that the client needs to authenticate for network access.
2. Send Response: The server sends a 511 Network Authentication Required response to the client.

Scenarios

• Restricted Network Access: Used in scenarios where network access is restricted, and authentication is required.

Sequence Diagram

Illustrating the process for an HTTP 511 response:

sequenceDiagram
    participant Client
    participant Server

    Note over Client: Step 1: Client attempts to access a resource
    Client->>Server: GET /network-resource HTTP/1.1 (Step 1)

    Note over Server: Step 2: Server identifies the need for network authentication
    Server-->>Client: HTTP/1.1 511 Network Authentication Required (Step 2)

Curl Request and Response Example

Attempting to access a resource that requires network authentication using Curl:

curl -i http://example.com/network-resource
# Expected response: HTTP/1.1 511 Network Authentication Required

PHP cURL Request and Response Example

PHP script using cURL to handle a 511 Network Authentication Required response:

<?php
$ch = curl_init('http://example.com/network-resource');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);
if (curl_getinfo($ch, CURLINFO_HTTP_CODE) == 511) {
    echo "Network Authentication Required";
}
curl_close($ch);
?>

Python Request and Response Example

Python script attempting to access a resource that requires network authentication and handling a 511 Network Authentication Required response:

import requests
response = requests.get('http://example.com/network-resource')
if response.status_code == 511:
    print("Network Authentication Required")

Apache Configuration for HTTP 511 Network Authentication Required

Configuring Apache to handle 511 errors:

# Apache Configuration Example
ErrorDocument 511 "Network Authentication Required"

NGINX Configuration for HTTP 511 Network Authentication Required

NGINX configuration for handling 511 errors:

# NGINX Configuration Example
error_page 511 /511.html;
location = /511.html {
    internal;
    return 511 "Network Authentication Required";
}