511 Network Authentication Required

511

Network Authentication Required

⚙️

Example HTTP Response

HTTP Response

HTTP/1.1 511 Network Authentication Required
Content-Type: text/html

<html><body>Please log in to access the network</body></html>

Common Causes

Captive portal requiring login
Network access requires authentication
Hotel or airport Wi-Fi gateway

Technical Details

What does this mean?

Wi-Fi login time! You've connected to a network that wants you to sign in first. Usually that annoying coffee shop or airport portal.

Technical Definition

The client needs to authenticate to gain network access, often used by captive portals.

RFC Says

"The 511 (Network Authentication Required) status code indicates that 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."

Plain English:

511 means 'You need to log in to the network (like a WiFi captive portal) before you can access the internet.' This is commonly seen at coffee shops, hotels, and airports. It's not about authenticating with the destination server (that's 401) - it's about authenticating with the network itself.

Common Misinterpretation

Don't use 511 for application authentication - use 401 or 403. Use 511 only for captive portals and network-level authentication. Most application developers will never need to return 511 - it's returned by network infrastructure, not application servers.

View RFC Documentation

Code Snippets

Ready-to-use code for returning this HTTP status in your application:

Node.js

// Express.js
app.get('/example', (req, res) => {
  res.status(511).json({
    error: 'Network Authentication Required',
    message: 'Your error message here'
  });
});

// Native HTTP
const http = require('http');

http.createServer((req, res) => {
  res.writeHead(511, { 'Content-Type': 'application/json' });
  res.end(JSON.stringify({
    error: 'Network Authentication Required',
    message: 'Your error message here'
  }));
}).listen(3000);

511 Network Authentication Required FAQ

What causes a 511 Network Authentication Required error?

Captive portal requiring login. Network access requires authentication. Hotel or airport Wi-Fi gateway.

// Express.js app.get('/example', (req, res) => { res.status(511).json({ error: 'Network Authentication Required', message: 'Your error message here' }); }); // Native HTTP const http = require('http'); http.createServer((req, res) => { res.writeHead(511, { 'Content-Type': 'application/json' }); res.end(JSON.stringify({ error: 'Network Authentication Required', message: 'Your error message here' })); }).listen(3000);