Use this page to collect tips on how to troubleshoot IPv6 issues. For instance, adding an AAAA record for a service to your DNS may result in a small percentage of end-users losing connectivity and others experiencing unusually high latency. The root cause for connectivity loss is usually that the end user is on another network with IPv6 on their PC but no form of IPv6 connectivity. In fact, their company may be blocking Teredo and 6to4 traffic. The root cause for high latency is usually that the end user is using some form of tunnel (ISATAP, tunnel broker, 6to4, Teredo) that causes their traffic to trombone out to a distant tunnel endpoint and then come back again, or perhaps the tunnel endpoint is on a network that has poor IPv6 connectivity.

As you deploy IPv6 and as other networks deploy IPv6, your helpdesk will see new and different problems. Also, problems that seem familiar will turn out to have different root causes from before. You will need to deal with this issue even if you are delaying implementation of IPv6 in your own network.

In order to debug connectivity issues, you can easily traceroute from various places to your network by setting up an IPv4-only host and setting up various kinds of transition technologies on it (6to4, Teredo, gogo6 and SixXS tunnels, etc.)

Verifying the IPv6 Experience

It may not be initially obvious, but your IPv6 throughput may not be the same as your IPv4 throughput.

In addition to their service provider's topology, an end-users' local IPv6 environment may result in poor IPv6 throughput.

Identify your IPv6 address

Test your IPv6-based browsing connectivity

Test your e-mail server connectivity

Test webmail

Test FTP access

Test NTP access

Test Telnet access

Test Performance

The only way to know the actual 'goodput' of your IPv6 link is to measure that with an IPv6-based test. Here are some IPv6 "speed test" sites:

Here are some large files accessible over IPv6:

Here are some IPv6-capable throughput software tools:

Test Network Connectivity

Thorough diagnostic tests of network links (both require Java)

Without Java - http://test-ipv6.se/ and http://test-ipv6.com/ 

Test PMTUD

Test support of Extension Headers

Test Website

If you host a website and want to test your end users' IPv6 access:

Test IPv6 readiness of a domain

Test for open ports

Here are some web sites that use an NMAP scan over IPv6 to test for open ports on the visitor's address