My subnet (R2458 2001:6f8:131c::/48) currently appears to be unreachable, although the tunnel itself (T2194 80.190.98.211 2001:6f8:900:103::2) is working fine. traceroutes to the subnet only get as far as deham01, e.g Router: uk-hex.nordu.net Command: 'traceroute ipv6.cmeerw.net' traceroute6 to ipv6.cmeerw.net (2001:6f8:131c::1) from 2001:948:0:f00b::2, 64 hops max, 12 byte packets 1 dk-ore.nordu.net (2001:948:0:f00b::1) 23.968 ms 21.338 ms 21.335 ms 2 dk-uni.nordu.net (2001:948:0:f055::2) 21.822 ms 21.815 ms 21.797 ms 3 nl-sar.nordu.net (2001:948:0:f058::2) 34.834 ms 34.818 ms 34.803 ms 4 te3-0-0.gr10.saams.nl.easynet.net (2001:7f8:1::a500:4589:1) 37.586 ms 54.619 ms 42.243 ms 5 2001:6f8:1:0:87:86:77:115 (2001:6f8:1:0:87:86:77:115) 115.952 ms 84.102 ms 94.986 ms 6 2001:6f8:1:0:87:86:71:229 (2001:6f8:1:0:87:86:71:229) 41.935 ms 41.750 ms 41.932 ms 7 ge1-14-151.br3.isham.de.easynet.net (2001:6f8:800:0:1:0:d4e0:5e0) 47.619 ms 47.580 ms 47.587 ms 8 ge9-15.cr20.isham.de.easynet.net (2001:6f8:800:0:1:0:d4e0:45d) 47.594 ms 47.426 ms 47.495 ms 9 deham01.sixxs.net (2001:6f8:800:1003::2) 56.478 ms !N 49.262 ms !N 48.978 ms !N Router: swiCE2.switch.ch Command: trace ipv6.cmeerw.net Type escape sequence to abort. Tracing the route to ipv6.cmeerw.net (2001:6F8:131C::1) 1 swiCE3-10GE-1-4.switch.ch (2001:620:0:C03D::2) 0 msec 0 msec 0 msec 2 2001:918:0:1A::1 4 msec 0 msec 0 msec 3 2001:918:0:13::1 0 msec 0 msec 0 msec 4 2001:918:0:12::2 4 msec 4 msec 4 msec 5 2001:918:0:1F::2 4 msec 4 msec 4 msec 6 2001:918:0:14::2 12 msec 12 msec 12 msec 7 fe0-1-2-0.br1.ixfra.de.easynet.net (2001:7F8::11ED:0:1) 16 msec 20 msec 12 msec 8 2001:6F8:1:0:87:86:77:246 40 msec 208 msec 212 msec 9 2001:6F8:1:0:87:86:71:229 12 msec 12 msec 12 msec 10 ge1-14-151.br3.isham.de.easynet.net (2001:6F8:800:0:1:0:D4E0:5E0) 20 msec 24 msec 20 msec 11 ge9-15.cr20.isham.de.easynet.net (2001:6F8:800:0:1:0:D4E0:45D) 24 msec 20 msec 20 msec 12 deham01.sixxs.net (2001:6F8:800:1003::2) !U !U !U But a traceroute to the IPv6 tunnel address works fine, e.g. Router: swiCE2.switch.ch Command: trace 2001:6f8:900:103::2 Type escape sequence to abort. Tracing the route to cl-260.ham-01.de.sixxs.net (2001:6F8:900:103::2) 1 swiCE3-10GE-1-4.switch.ch (2001:620:0:C03D::2) 0 msec 0 msec 0 msec 2 2001:918:0:1A::1 0 msec 0 msec 4 msec 3 2001:918:0:13::1 0 msec 0 msec 0 msec 4 2001:918:0:12::2 4 msec 4 msec 4 msec 5 2001:918:0:1F::2 4 msec 4 msec 4 msec 6 2001:918:0:14::2 12 msec 12 msec 12 msec 7 fe0-1-2-0.br1.ixfra.de.easynet.net (2001:7F8::11ED:0:1) 12 msec 12 msec 12 msec 8 2001:6F8:1:0:87:86:77:246 16 msec 16 msec 12 msec 9 2001:6F8:1:0:87:86:71:229 12 msec 12 msec 12 msec 10 ge1-14-151.br3.isham.de.easynet.net (2001:6F8:800:0:1:0:D4E0:5E0) 20 msec 24 msec 20 msec 11 ge9-15.cr20.isham.de.easynet.net (2001:6F8:800:0:1:0:D4E0:45D) 24 msec 20 msec 24 msec 12 deham01.sixxs.net (2001:6F8:800:1003::2) 24 msec 20 msec 28 msec 13 cl-260.ham-01.de.sixxs.net (2001:6F8:900:103::2) 48 msec 44 msec 40 msec