HTTP status code

The HTTP 407 status code stands for "Proxy Authentication Required". It is a client error response indicating that the client must authenticate with a proxy server in order to access the requested resource. This is similar to the HTTP 401 Unauthorized response but specifically applies to requests that go through a proxy.

When is HTTP 407 Used?

• When the client is trying to access a resource through a proxy server, and the server requires authentication.
• When the proxy server needs the client to provide credentials (e.g., username and password) to permit access.
• This can occur in situations where a network or corporate environment uses a proxy to filter or control web access.

How Does It Work?

The server responds with a 407 status code and provides information in the Proxy-Authenticate header, which tells the client how to authenticate with the proxy server.

Common Causes of HTTP 407 Errors

• Proxy requires authentication but the client has not provided credentials.
• Invalid or expired proxy credentials.
• Proxy authentication misconfiguration in network settings.

Example Scenarios

• Corporate networks that use a proxy to filter traffic.
• Accessing restricted web resources in an environment that uses a proxy server for network security.
• Misconfigured proxy settings where the client doesn't know the correct credentials.

Example

Client Request (Attempting to Access Resource via Proxy)

    
       GET /secure-data HTTP/1.1
        Host: example.com
    

Server Response (407 Proxy Authentication Required)

    
        HTTP/1.1 407 Proxy Authentication Required
        Proxy-Authenticate: Basic realm="Proxy Authentication Required"
        Content-Type: application/json

        { "error": "Proxy authentication required. Please provide valid credentials." }
    

Key Header: Proxy-Authenticate

The Proxy-Authenticate header tells the client what authentication scheme to use when providing the proxy credentials. Common schemes include Basic or Digest.

Best Practices for Handling HTTP 407

• Configure proxy authentication properly on the client side.
• Ensure that proxy credentials are up to date and correct.
• Use proxy servers securely by encrypting communications (e.g., via HTTPS).

Summary

HTTP 407 means the client must authenticate with a proxy server before accessing the requested resource. It typically happens in network environments using a proxy for security or traffic management. The client must respond with the correct authentication credentials as specified in the Proxy-Authenticate header.