Hi, My tunnel seems to be enabled and up but I can not ping6 the PoP IPv6 (error : Destination unreachable: Address unreachable). The tcpdump (see logs behind) shows the echo request (packet IPv6 in IPv4 with proto 41) goes out but in response we have an ICMP error from the PoP IPv4 (protocol 41 unreachable). I can't find a problem on this side. Thanks for your reply. Migiel de Vos Please find my configuration : ---------------------------- Username : MV5-6BONE Tunnel ID : T5466 PoP Name : nlams05 PoP Location : Amsterdam, Netherlands, The PoP IPv4 : 192.87.102.107 Your IPv4 : unknown (not running on noc.sixxs.net) IPv6 Prefix : 2001:610:600:5d::1/64 PoP IPv6 : 2001:610:600:5d::1 Your IPv6 : 2001:610:600:5d::2 Created: 2004-12-02 20:14:44 CEST State : Enabled OS type : ------- Debian GNU/Linux 4.0 (etch) Linux x 2.6.26-2-686 #1 SMP Tue Mar 9 17:35:51 UTC 2010 i686 GNU/Linux interface : --------- sixxs Link encap:IPv6-in-IPv4 inet6 addr: 2001:610:600:5d::2/64 Scope:Global inet6 addr: fe80::9163:c37e/64 Scope:Link UP POINTOPOINT RUNNING NOARP MTU:1280 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:133 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 B) TX bytes:16492 (16.1 KiB) routing table : ------------- fw:~# ip -6 route show 2001:610:600:5d::/64 via :: dev sixxs metric 256 mtu 1280 advmss 1220 hoplimit 4294967295 fe80::/64 dev eth0 metric 256 mtu 1500 advmss 1440 hoplimit 4294967295 fe80::/64 via :: dev sixxs metric 256 mtu 1280 advmss 1220 hoplimit 4294967295 default via 2001:610:600:5d::1 dev sixxs metric 1024 mtu 1280 advmss 1220 hoplimit 4294967295 ping PoP IPv4 (OK) : ------------- x:~# ping 192.87.102.107 PING 192.87.102.107 (192.87.102.107) 56(84) bytes of data. 64 bytes from 192.87.102.107: icmp_seq=1 ttl=58 time=14.8 ms 64 bytes from 192.87.102.107: icmp_seq=2 ttl=58 time=14.1 ms ping my IPv6 (OK) : ------------ x:~# ping6 2001:610:600:5d::2 PING 2001:610:600:5d::2(2001:610:600:5d::2) 56 data bytes 64 bytes from 2001:610:600:5d::2: icmp_seq=1 ttl=64 time=0.069 ms 64 bytes from 2001:610:600:5d::2: icmp_seq=2 ttl=64 time=0.041 ms ping PoP IPv6 (NO) : ------------- x:~# ping6 2001:610:600:5d::1 PING 2001:610:600:5d::1(2001:610:600:5d::1) 56 data bytes x:~# tcpdump -n -i eth0 proto 41 ---------------------------------- listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes 21:51:57.711194 IP MYIP > 192.87.102.107: IP6 2001:610:600:5d::2 > 2001:610:1:80d0:194:171:26:201: ICMP6, echo request, seq 2492, length 64 21:51:58.711171 IP MYIP > 192.87.102.107: IP6 2001:610:600:5d::2 > 2001:610:1:80d0:194:171:26:201: ICMP6, echo request, seq 2493, length 64 x:~# tcpdump -n -i eth0 icmp ------------------------------ nothing happens here..