I'm unable to pass traffic out of uslax02 (MHC1-SIXXS/T107194) between two of my sixxs tunnels. Some other traffic such as Google is fine. While I can reach the tunnel endpoint of my usqas01 tunnel T12632, I can't reach the subnet behind it. But other IPv6 hosts I have can reach the subnet successfully, indicating it's probably not a problem at my local network on either end. From 2607:f878:fe00:24::2 # traceroute6 2001:4830:1600:80bf:6e62:6dff:fed1:dfad traceroute to 2001:4830:1600:80bf:6e62:6dff:fed1:dfad (2001:4830:1600:80bf:6e62:6dff:fed1:dfad), 30 hops max, 80 byte packets 1 gw-37.lax-02.us.sixxs.net (2607:f878:fe00:24::1) 1.875 ms 1.842 ms 1.823 ms 2 uslax02.sixxs.net (2607:f878:3:400::2) 1.803 ms 1.756 ms 1.740 ms 3 2607:f878:3:a::1 (2607:f878:3:a::1) 2.048 ms 2.370 ms 2.617 ms 4 2607:f878::1d0 (2607:f878::1d0) 2.934 ms 2.922 ms 2.995 ms 5 2607:f878::18a (2607:f878::18a) 2.790 ms 2.799 ms 2.920 ms 6 2607:f878::158 (2607:f878::158) 88.141 ms 89.131 ms 89.514 ms 7 2607:f878::32e (2607:f878::32e) 89.501 ms 89.489 ms 89.467 ms 8 2607:f878::333 (2607:f878::333) 89.450 ms 90.729 ms 90.686 ms 9 2607:f878::333 (2607:f878::333) 88.815 ms 88.814 ms 89.873 ms 10 2607:f878::335 (2607:f878::335) 89.903 ms 89.898 ms 89.892 ms 11 2607:f878::333 (2607:f878::333) 89.814 ms 89.776 ms 91.645 ms 12 2607:f878::335 (2607:f878::335) 91.916 ms 93.307 ms 93.857 ms 13 2607:f878::333 (2607:f878::333) 91.787 ms 91.787 ms 91.800 ms 14 2607:f878::335 (2607:f878::335) 93.780 ms 98.727 ms 98.671 ms 15 2607:f878::333 (2607:f878::333) 89.335 ms 89.564 ms * 16 2607:f878::335 (2607:f878::335) 89.861 ms 90.850 ms * 17 * * * 18 2607:f878::335 (2607:f878::335) 91.268 ms * * 19 * * 2607:f878::333 (2607:f878::333) 90.623 ms 20 * * * 21 * * * 22 * 2607:f878::335 (2607:f878::335) 93.535 ms 93.480 ms 23 2607:f878::333 (2607:f878::333) 92.216 ms 92.277 ms 92.495 ms 24 2607:f878::335 (2607:f878::335) 93.513 ms 93.897 ms 94.856 ms 25 2607:f878::333 (2607:f878::333) 92.436 ms 92.430 ms 93.166 ms 26 2607:f878::335 (2607:f878::335) 94.795 ms 94.785 ms 94.781 ms 27 2607:f878::333 (2607:f878::333) 93.144 ms 93.151 ms 94.689 ms 28 2607:f878::335 (2607:f878::335) 94.891 ms 94.844 ms * 29 2607:f878::333 (2607:f878::333) 94.527 ms * 91.429 ms 30 2607:f878::335 (2607:f878::335) 92.256 ms * * Reaching the tunnel endpoint works: # traceroute6 2001:4830:1600:bf::2 traceroute to 2001:4830:1600:bf::2 (2001:4830:1600:bf::2), 30 hops max, 80 byte packets 1 gw-37.lax-02.us.sixxs.net (2607:f878:fe00:24::1) 1.174 ms 1.150 ms 1.139 ms 2 uslax02.sixxs.net (2607:f878:3:400::2) 1.984 ms 1.980 ms 1.966 ms 3 2607:f878:3:a::1 (2607:f878:3:a::1) 3.905 ms 3.911 ms 3.899 ms 4 2607:f878::188 (2607:f878::188) 3.890 ms 3.831 ms 3.805 ms 5 2607:f878::158 (2607:f878::158) 110.354 ms 110.422 ms 110.413 ms 6 2607:f878::32e (2607:f878::32e) 88.589 ms 96.868 ms 96.781 ms 7 2607:f878::335 (2607:f878::335) 97.200 ms 97.128 ms 97.116 ms 8 2607:f878::333 (2607:f878::333) 96.826 ms 96.896 ms 96.951 ms 9 2607:f878::33a (2607:f878::33a) 286.834 ms 287.577 ms 287.579 ms 10 xe-5-2-1.edge3.Newark1.Level3.net (2001:1900:2100::1dbd) 107.016 ms 112.822 ms 113.014 ms 11 vl-52.car2.Newark1.Level3.net (2001:1900:34:2::4) 101.177 ms 101.207 ms 101.163 ms 12 vl-4063.edge2.Washington1.Level3.net (2001:1900:4:1::ca) 101.128 ms 99.736 ms 99.777 ms 13 vl-4085.sar1.Washington1.Level3.net (2001:1900:4:1::251) 103.704 ms 103.531 ms 103.626 ms 14 ibr01-ve96.asbn01.occaid.net (2001:504:0:2:0:3:71:1) 104.819 ms 104.814 ms 105.003 ms 15 equi6ix.dc.hotnic.net (2001:504:0:2:0:3:3437:1) 105.106 ms 105.103 ms 105.449 ms 16 sixxs-asbnva-gw.customer.occaid.net (2001:4830:e6:7::2) 104.241 ms 104.008 ms 100.397 ms 17 gw-192.qas-01.us.sixxs.net (2001:4830:1600:bf::1) 100.768 ms 101.208 ms 101.345 ms 18 cl-192.qas-01.us.sixxs.net (2001:4830:1600:bf::2) 152.782 ms 156.025 ms 155.967 ms Expected behavior (reaching the subnet from a different tunnel usphx01 T100102 works): traceroute6 2001:4830:1600:80bf:6e62:6dff:fed1:dfad traceroute to 2001:4830:1600:80bf:6e62:6dff:fed1:dfad (2001:4830:1600:80bf:6e62:6dff:fed1:dfad), 30 hops max, 80 byte packets 1 2001:1938:81:82f2::1 (2001:1938:81:82f2::1) 0.273 ms 0.329 ms 0.306 ms 2 gw-755.phx-01.us.sixxs.net (2001:1938:81:2f2::1) 2.112 ms 2.098 ms 2.176 ms 3 2001:4de0:1000:a4::2 (2001:4de0:1000:a4::2) 2.276 ms 2.380 ms 2.361 ms 4 2001:4de0:1000:a4::1 (2001:4de0:1000:a4::1) 12.035 ms 12.265 ms 12.342 ms 5 1-3.ipv6.r1.ph.hwng.net (2001:4de0:1000:27::2) 3.757 ms 3.841 ms 3.949 ms 6 2-1.ipv6.r3.da.hwng.net (2001:4de0:1000:1c::2) 26.705 ms 26.460 ms 26.391 ms 7 7-1.ipv6.r1.at.hwng.net (2001:4de0:1000:1d::2) 82.852 ms 57.136 ms 57.207 ms 8 2-1.ipv6.r2.dc.hwng.net (2001:4de0:1000:7::1) 63.070 ms 65.060 ms 72.367 ms 9 2-3.ipv6.r1.dc.hwng.net (2001:4de0:1000:9::1) 73.872 ms 73.923 ms 62.363 ms 10 ibr01-ve96.asbn01.occaid.net (2001:504:0:2:0:3:71:1) 64.613 ms 64.110 ms 64.672 ms 11 equi6ix.dc.hotnic.net (2001:504:0:2:0:3:3437:1) 63.389 ms 63.243 ms 64.146 ms 12 sixxs-asbnva-gw.customer.occaid.net (2001:4830:e6:7::2) 64.615 ms 64.685 ms 68.430 ms 13 gw-192.qas-01.us.sixxs.net (2001:4830:1600:bf::1) 68.177 ms 65.207 ms 67.081 ms 14 2001:4830:1600:80bf:6e62:6dff:fed1:dfad (2001:4830:1600:80bf:6e62:6dff:fed1:dfad) 118.647 ms 114.223 ms 133.048 ms This leads me to believe the problem is at uslax02.