← All Status Codes
511
Network Auth Required
🔴 Server Error
Medium Risk
📖 What Is HTTP 511?
The client needs to authenticate to gain network access. Used by captive portals (hotel Wi-Fi, airport Wi-Fi) to redirect users to a login page.
🛡️ Security Implications
Captive portals intercept HTTPS traffic which can be exploited for MITM attacks. Always verify you are on the real login page.
🔍 Common Causes
Connecting to Wi-Fi that requires login (hotel, airport, coffee shop). Network requires terms acceptance or payment.
🔧 How to Fix
Open a browser and navigate to any HTTP site to trigger the captive portal redirect. Accept terms or authenticate to gain access.
🖥️ How to Check
curl -I -o /dev/null -w "%{http_code}" https://example.com