Home › Docs › How to Troubleshoot "No IPv6 Connectivity"

How to Troubleshoot "No IPv6 Connectivity"

When you encounter "No IPv6 connectivity" errors, it can be frustrating to diagnose where the problem lies. This comprehensive guide walks you through a systematic approach to identify and resolve IPv6 connectivity issues, from verifying basic support to fixing complex configuration problems.

Quick Diagnostic Checklist

Before diving into troubleshooting, use this checklist to quickly assess your situation:

Step 1: Verify the Problem with Online Testing

Start here every time. Before making any changes to your system, confirm that you actually have an IPv6 connectivity problem.

Visit test-ipv6.run to run comprehensive connectivity tests. This tool tests:

What the results mean:

If the test shows no IPv6 connectivity, proceed to the next steps to diagnose the root cause.

Step 2: Check ISP Support First

This is the most common reason for no IPv6 connectivity. Many Internet Service Providers (ISPs) still do not offer IPv6 support, especially in residential areas. For more information, see our ISP IPv6 deployment status guide.

How to Verify ISP Support

Contact your ISP:

Check your modem's WAN address:

What to do if ISP doesn't support IPv6:

If your ISP supports IPv6 but you don't have connectivity, proceed to Step 3.

Step 3: Verify Router Configuration

Your router must be properly configured to request and distribute IPv6 addresses to your network. See our guide on enabling IPv6 on routers for detailed instructions.

Router Configuration Checklist

Access your router admin panel:

Check IPv6 settings:

Verify router has obtained IPv6 addresses:

Common router issues:

Testing Router Configuration

After making changes, reboot your router and test again at test-ipv6.run.

Step 4: Check Client Device Configuration

Even with proper ISP and router support, your device must be configured correctly to use IPv6. For a quick check of your device's IPv6 status, see how to check device IPv6 connectivity.

Windows Configuration

Check IPv6 address assignment:

  1. Open Command Prompt (cmd)
  2. Run: ipconfig /all
  3. Look for "IPv6 Address" entries under your network adapter

What you should see:

If you don't see a global IPv6 address:

Enable IPv6 on network adapter:

  1. Open Network Connections (ncpa.cpl)
  2. Right-click your network adapter → Properties
  3. Ensure "Internet Protocol Version 6 (TCP/IPv6)" is checked
  4. Click OK and restart your network adapter

Reset network stack if needed:

netsh int ip reset
netsh winsock reset
ipconfig /flushdns

Restart your computer after running these commands.

macOS Configuration

Check IPv6 address:

ifconfig en0 | grep inet6

Verify IPv6 is configured:

  1. Open System Preferences → Network
  2. Select your active connection → Advanced → TCP/IP
  3. Ensure "Configure IPv6" is set to "Automatically"

Linux Configuration

Check IPv6 address:

ip -6 addr show

Verify IPv6 default route:

ip -6 route | grep default

Check if IPv6 is disabled:

cat /proc/sys/net/ipv6/conf/all/disable_ipv6

Should return 0 (enabled). If it returns 1, IPv6 is disabled at the kernel level.

Step 5: Review Firewall and Security Software

Firewalls and security software can block essential IPv6 traffic, causing connectivity to fail even when everything else is configured correctly. For comprehensive firewall guidance, see our IPv6 firewall configuration guide.

Critical IPv6 Traffic Types

IPv6 requires specific ICMPv6 traffic to function properly:

If any of these are blocked, IPv6 will not work.

Windows Firewall Configuration

Issue: Windows "Block all incoming connections" setting can break IPv6 by blocking ICMPv6.

Solution: Create custom inbound firewall rules:

  1. Open Windows Defender Firewall with Advanced Security
  2. Click "Inbound Rules" → "New Rule"
  3. Select "Custom" → Next
  4. Protocol Type: ICMPv6
  5. Select specific ICMP types to allow:
    • Echo Request (ping)
    • Echo Reply (ping response)
    • Neighbor Solicitation
    • Neighbor Advertisement
    • Router Solicitation
    • Router Advertisement
  6. Apply to all profiles (Domain, Private, Public)
  7. Name the rule "Allow Essential IPv6 ICMPv6"

Third-Party Antivirus/Firewall

Many security suites have separate IPv6 filtering:

Router Firewall

Some routers have overly restrictive IPv6 firewall settings:

Step 6: Troubleshoot DNS Issues

DNS problems can prevent IPv6 connectivity even when network configuration is correct. For more detailed DNS troubleshooting, see our IPv6 DNS failures guide.

Understanding DNS and IPv6

Testing DNS Resolution

Windows:

nslookup -type=AAAA test-ipv6.run

macOS/Linux:

dig AAAA test-ipv6.run
host -t AAAA test-ipv6.run

Expected result: Should return IPv6 addresses (starting with 2xxx:).

If queries fail:

Switch to IPv6-Capable DNS Servers

Configure your device to use public DNS servers that support IPv6:

Google Public DNS:

Cloudflare DNS:

How to change DNS (Windows):

  1. Network Connections → Network adapter properties
  2. Select "Internet Protocol Version 6 (TCP/IPv6)" → Properties
  3. Select "Use the following DNS server addresses"
  4. Enter preferred and alternate DNS servers
  5. Click OK

After changing DNS:

Step 7: Update Network Drivers

Outdated or faulty network adapter drivers are a surprisingly common cause of IPv6 connectivity issues.

Windows Driver Update

Automatic update:

  1. Device Manager → Network adapters
  2. Right-click your adapter → Update driver
  3. Select "Search automatically for updated driver software"

Manual update:

  1. Visit your computer or network adapter manufacturer's website
  2. Download the latest driver for your specific model
  3. Install and restart

Verify driver update fixed the issue

After updating drivers, restart your computer and test at test-ipv6.run.

Step 8: Advanced Diagnostics

If basic troubleshooting hasn't resolved your issue, use these advanced diagnostic techniques.

Ping Testing

Test IPv6 connectivity to known servers:

Windows:

ping -6 google.com
ping 2001:4860:4860::8888

macOS/Linux:

ping6 google.com
ping6 2001:4860:4860::8888

Possible results:

Traceroute

Trace the path to IPv6 destinations:

Windows:

tracert -6 google.com

macOS/Linux:

traceroute6 google.com

This shows where IPv6 packets are getting dropped.

Check for IPv6 Privacy Extensions

Privacy extensions can sometimes cause connectivity issues:

Windows:

netsh interface ipv6 show privacy

Try disabling privacy extensions temporarily:

netsh interface ipv6 set privacy state=disabled

Troubleshooting Flowchart

┌─────────────────────────────────┐
│ Test at [test-ipv6.run](https://test-ipv6.run)           │
│ Do you have IPv6 connectivity?  │
└─────────────┬───────────────────┘
              │
         No   │   Yes
    ┌─────────┴────────┐
    │                  │
    ▼                  ▼
┌────────────────┐  ┌──────────────────┐
│ Does ISP       │  │ Issue is likely  │
│ support IPv6?  │  │ application or   │
└───┬────────────┘  │ site-specific    │
    │               └──────────────────┘
    │ No         Yes
    │    ┌──────────┘
    │    │
    ▼    ▼
┌──────────────┐  ┌────────────────────┐
│ Contact ISP  │  │ Is IPv6 enabled    │
│ or use IPv6  │  │ on router?         │
│ tunnel       │  └───┬────────────────┘
└──────────────┘      │
                      │ No      Yes
                 ┌────┴─────┐   │
                 │          │   │
                 ▼          │   ▼
          ┌──────────────┐ │ ┌────────────────────┐
          │ Enable IPv6  │ │ │ Does device have   │
          │ in router    │ │ │ global IPv6 addr?  │
          │ settings     │ │ └───┬────────────────┘
          └──────────────┘ │     │
                 │         │     │ No      Yes
                 └─────────┘     │    ┌────┴────┐
                           ┌─────┘    │         │
                           │          │         ▼
                           ▼          │   ┌──────────────┐
                    ┌──────────────┐ │   │ Check        │
                    │ Enable IPv6  │ │   │ firewall     │
                    │ on device,   │ │   │ and DNS      │
                    │ reset stack  │ │   │ settings     │
                    └──────────────┘ │   └──────────────┘
                           │         │
                           └─────────┘
                                 │
                                 ▼
                    ┌────────────────────┐
                    │ Update network     │
                    │ drivers and retest │
                    └────────────────────┘

Common Error Messages and Solutions

"IPv6 Connectivity: No Internet Access" (Windows)

Cause: Device has IPv6 enabled but cannot reach the Internet via IPv6.

Solution:

  1. Check router IPv6 configuration
  2. Verify ISP provides IPv6
  3. Reset network stack with netsh int ip reset
  4. Update network drivers

"IPv6 No Network Access"

Cause: Device cannot communicate even on local network via IPv6.

Solution:

  1. Check if IPv6 is enabled on network adapter
  2. Verify router is sending Router Advertisement messages
  3. Check for firewall blocking ICMPv6
  4. Disable and re-enable network adapter

Timeout on IPv6 Tests (Broken IPv6)

Cause: IPv6 is partially configured but traffic is being dropped somewhere.

Solution:

  1. This is worse than no IPv6 because it causes delays
  2. Check ISP/router firewall rules
  3. Disable IPv6 privacy extensions
  4. As a last resort, disable IPv6 entirely if not needed

When to Disable IPv6

In some cases, it may be better to disable IPv6 entirely:

How to disable IPv6 (Windows):

  1. Network adapter properties
  2. Uncheck "Internet Protocol Version 6 (TCP/IPv6)"
  3. Click OK and restart

Note: Disabling IPv6 is a workaround, not a fix. IPv6 is the future of the Internet, and you should aim to have it working properly.

Conclusion

Troubleshooting IPv6 connectivity requires a systematic approach, starting with verification at test-ipv6.run and working through ISP support, router configuration, device settings, firewall rules, DNS, and drivers. Most "no IPv6 connectivity" issues stem from lack of ISP support or disabled router settings, which are easy to check first.

By following this guide step-by-step, you can identify and resolve the majority of IPv6 connectivity problems. If you've exhausted all troubleshooting steps and still don't have IPv6 connectivity, contact your ISP's technical support for assistance.

Remember: Always test your changes at test-ipv6.run after each troubleshooting step to verify whether the issue is resolved.