I have read and followed the "Reporting Problems" section on the Contact page and am providing the following details for this report based on the list of items stated there: My tunnel connection is up, I have a subnet and this tunnel was setup to evaluate ipv6. This tunnel is running on a cisco 7206 router, configured by a very capable network staff. All changed on this router are logged. Nobody has made a configuration change to this router in 4 weeks. All of the sudden our ipv6 tunnel is down. We have verified the config and rebooted the router. The problem is not on our side. The two traceroutes listed below differ at hop 8. The traceroutes should be the same with only one extra line that refers to our tunnel endpoint. I believe their may be some kind of routing error. Look at the following trace routes. The first is a traceroute to your side of the ipv6 tunnel, and the second is mine. They should not be different but they are. traceroute to 2001:4830:1600:143::1 (2001:4830:1600:143::1), 30 hops max, 40 byte packets 1 subnetonline.tunnel.tserv11.ams1.ipv6.he.net (2001:470:1f14:e7::1) 1.976 ms 2.072 ms 2.202 ms 2 gige-g2-20.core1.ams1.he.net (2001:470:0:7d::1) 2.393 ms 2.648 ms 2.634 ms 3 10gigabitethernet1-4.core1.lon1.he.net (2001:470:0:3f::1) 10.517 ms 10.505 ms 10.492 ms 4 ibr01-ve26.lndn01.occaid.net (2001:7f8:4::7577:1) 10.478 ms 10.465 ms 10.461 ms 5 bbr01-p1-0.nwrk01.occaid.net (2001:4830:fe:1010::2) 85.126 ms 85.114 ms 85.100 ms 6 bbr01-g1-0.asbn01.occaid.net (2001:4830:ff:f150::2) 113.241 ms 112.649 ms 112.780 ms 7 equi6ix.dc.hotnic.net (2001:504:0:2:0:3:3437:1) 112.370 ms 112.776 ms 113.040 ms 8 gw-324.qas-01.us.sixxs.net (2001:4830:1600:143::1) 113.300 ms 112.772 ms 113.069 ms Finished! TraceRoute IPv6 Output: traceroute to 2001:4830:1600:143::2 (2001:4830:1600:143::2), 30 hops max, 40 byte packets 1 subnetonline.tunnel.tserv11.ams1.ipv6.he.net (2001:470:1f14:e7::1) 2.109 ms 2.494 ms 2.462 ms 2 gige-g2-20.core1.ams1.he.net (2001:470:0:7d::1) 2.480 ms 2.450 ms 2.524 ms 3 10gigabitethernet1-4.core1.lon1.he.net (2001:470:0:3f::1) 10.131 ms 10.263 ms 10.234 ms 4 ibr01-ve26.lndn01.occaid.net (2001:7f8:4::7577:1) 10.410 ms 10.380 ms 10.349 ms 5 bbr01-p1-0.nwrk01.occaid.net (2001:4830:fe:1010::2) 85.063 ms 85.034 ms 85.003 ms 6 bbr01-g1-0.asbn01.occaid.net (2001:4830:ff:f150::2) 112.841 ms 112.039 ms 111.406 ms 7 equi6ix.dc.hotnic.net (2001:504:0:2:0:3:3437:1) 111.709 ms 111.495 ms 111.852 ms 8 sixxs-asbnva-gw.customer.occaid.net (2001:4830:e6:7::2) 112.734 ms 111.561 ms 111.574 ms 9 * * * 10 * * * 11 * * * These routes are completely different and they should not be