For developers working with IPv6 networking, here are some reliable public test addresses similar to IPv4's 8.8.8.8:

• 2001:4860:4860::8888 (Google DNS)
• 2001:4860:4860::8844 (Google DNS secondary)
• 2606:4700:4700::1111 (Cloudflare DNS)
• 2620:fe::fe (Quad9 DNS)

Here's how to test basic IPv6 connectivity using these addresses:

# Linux/macOS
ping6 2001:4860:4860::8888

# Windows
ping -6 2001:4860:4860::8888

Verify DNS resolution over IPv6 with dig or nslookup:

# Using dig
dig @2001:4860:4860::8888 example.com AAAA

# Windows nslookup
nslookup example.com 2001:4860:4860::8888

Python example to test IPv6 connectivity:

import socket

def test_ipv6_connectivity(address="2001:4860:4860::8888", port=53):
    try:
        sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
        sock.settimeout(5)
        sock.connect((address, port))
        print(f"Successfully connected to {address}")
        return True
    except socket.error as e:
        print(f"Connection failed: {e}")
        return False
    finally:
        sock.close()

test_ipv6_connectivity()

For web developers testing IPv6 in browsers:

• http://ipv6.google.com
• http://test-ipv6.com
• http://ipv6-test.com

For IPv6 network testing and diagnostics, these public addresses are widely recognized:

• 2001:4860:4860::8888 (Google Public DNS IPv6)
• 2001:4860:4860::8844 (Google Alternate DNS IPv6)
• 2606:4700:4700::1111 (Cloudflare DNS IPv6)
• 2620:119:35::35 (OpenDNS IPv6)

Here's how to test IPv6 connectivity in different programming languages:

Python Example

Testing connectivity to Google's IPv6 DNS:

import socket

def test_ipv6_connectivity():
    try:
        socket.create_connection(("2001:4860:4860::8888", 53), timeout=5)
        print("IPv6 connectivity successful")
    except socket.error:
        print("IPv6 connectivity failed")

test_ipv6_connectivity()

Bash Example

Simple ping test for IPv6:

ping6 -c 4 2001:4860:4860::8888

IANA has reserved certain IPv6 prefixes specifically for documentation and testing:

• 2001:db8::/32 - Documentation prefix (not routable)
• 2001:2::/48 - Benchmarking/testing prefix

These test addresses are particularly useful for:

• Validating IPv6 network stack implementation
• Testing dual-stack application behavior
• Verifying DNS resolution over IPv6
• Benchmarking IPv6 network performance

When using these test addresses:

• Always check if your local network supports IPv6
• Firewall rules may block ICMPv6/ping6 requests
• Some addresses may have rate limiting
• Consider using both ICMP and TCP-based tests