IPv6 Pattern Test - The script that revealed the hotel WiFi issue

gist_ipv6_pattern_test.py

#!/usr/bin/env python3
"""
IPv6 Pattern Test - The script that revealed the hotel WiFi issue

This is the actual script Claude Code wrote that tested multiple services
and revealed the pattern: all real IPv6 addresses failed at TLS,
while IPv6-mapped IPv4 addresses worked fine.

When run at home, everything worked - revealing it was the hotel WiFi
breaking IPv6 in a very specific way.

Usage: python ipv6_pattern_test.py
"""

import asyncio
import socket
import ssl
import time


async def test_service(name, host, port=443):
    """Test both IPv4 and IPv6 for a service."""
    print(f"\n{'='*60}")
    print(f"Testing: {name} ({host}:{port})")
    print('='*60)
    
    results = {}
    
    for ip_version in [6, 4]:
        family = socket.AF_INET if ip_version == 4 else socket.AF_INET6
        
        try:
            # Get address
            addr_info = socket.getaddrinfo(host, port, family=family, proto=socket.IPPROTO_TCP)
            if not addr_info:
                results[f'ipv{ip_version}'] = "No address"
                print(f"IPv{ip_version}: No address found")
                continue
                
            addr = addr_info[0][4]
            print(f"\nIPv{ip_version}: {addr[0]}")
            
            # TCP test
            sock = socket.socket(family, socket.SOCK_STREAM)
            sock.settimeout(5)
            
            try:
                sock.connect(addr)
                print(f"  ✅ TCP: Connected")
                
                # TLS test
                context = ssl.create_default_context()
                try:
                    ssock = context.wrap_socket(sock, server_hostname=host)
                    print(f"  ✅ TLS: Handshake successful")
                    results[f'ipv{ip_version}'] = "Full success"
                    ssock.close()
                except Exception as e:
                    print(f"  ❌ TLS: {type(e).__name__}: {str(e)[:50]}")
                    results[f'ipv{ip_version}'] = "TCP works, TLS fails"
                    sock.close()
                    
            except Exception as e:
                print(f"  ❌ TCP: {type(e).__name__}: {str(e)[:50]}")
                results[f'ipv{ip_version}'] = "TCP fails"
                
        except Exception as e:
            results[f'ipv{ip_version}'] = f"Error: {type(e).__name__}"
            print(f"IPv{ip_version}: Error - {type(e).__name__}")
    
    return results


async def main():
    """Test various services to show the pattern."""
    
    print("Comparing IPv6 behavior across different services")
    print("=" * 70)
    
    # Test various services
    services = [
        ("TikAPI", "api.tikapi.io"),
        ("Google", "www.google.com"),
        ("Cloudflare", "cloudflare.com"),
        ("GitHub", "api.github.com"),
        ("OpenAI", "api.openai.com"),
    ]
    
    all_results = {}
    
    for name, host in services:
        all_results[name] = await test_service(name, host)
    
    # Summary
    print("\n" + "="*70)
    print("📋 SUMMARY TABLE")
    print("="*70)
    print(f"{'Service':<15} {'IPv6 Status':<30} {'IPv4 Status':<25}")
    print("-"*70)
    
    ipv6_real_count = 0
    ipv6_mapped_count = 0
    ipv6_broken_count = 0
    
    for name, results in all_results.items():
        ipv6 = results.get('ipv6', 'Unknown')
        ipv4 = results.get('ipv4', 'Unknown')
        
        # Check for IPv6-mapped IPv4 addresses
        if 'ipv6' in results:
            try:
                addr_info = socket.getaddrinfo(services[list(all_results.keys()).index(name)][1], 443, socket.AF_INET6)
                if addr_info and addr_info[0][4][0].startswith('::ffff:'):
                    ipv6 = f"{ipv6} (IPv6-mapped IPv4)"
                    ipv6_mapped_count += 1
                else:
                    ipv6_real_count += 1
                    if ipv6 == "TCP works, TLS fails":
                        ipv6_broken_count += 1
            except:
                pass
        
        # Highlight the broken pattern
        if ipv6 == "TCP works, TLS fails":
            ipv6 = f"⚠️  {ipv6}"
            
        print(f"{name:<15} {ipv6:<30} {ipv4:<25}")
    
    # The revealing pattern
    print("\n" + "="*70)
    print("🔍 THE PATTERN THAT REVEALED THE TRUTH")
    print("="*70)
    
    if ipv6_broken_count == ipv6_real_count and ipv6_mapped_count > 0:
        print("\n🚨 ALL real IPv6 addresses fail at TLS!")
        print("✅ But IPv6-mapped IPv4 addresses work fine")
        print("\nThis pattern indicates:")
        print("- It's NOT just TikAPI that's broken")
        print("- The network/firewall is breaking IPv6 at TLS level")
        print("- This defeats Happy Eyeballs because TCP succeeds")
        print("\n💡 When this script works at home but fails at hotel/office,")
        print("   you've found an enterprise firewall breaking IPv6!")


if __name__ == "__main__":
    asyncio.run(main())