I'm trying to get my first tunnel up and running (T145665). My router reports the tunnel being up. I can ping the local and remote IPv4 address and I can ping my local IPv4 address. If I try to ping the IPv6 tunnel IP address on the Leaseweb site I see a protocol 41 unreachable in a packet capture. 20:31:34.499107 IP 94.210.218.46 > 94.75.219.73: IP6 2001:1af8:fe00:461::2 > 2001:1af8:fe00:461::1: ICMP6, echo request, seq 9, length 64 20:31:34.509201 IP 94.75.219.73 > 94.210.218.46: ICMP 94.75.219.73 protocol 41 unreachable, length 132 I also see heartbeat packets going to the remote IPv4 address port 3740, but I don't receive a response. show interfaces ethernet eth0 capture port 3740 Capturing traffic on eth0 port 3740 ... 21:17:02.739879 IP 94.210.218.46.48399 > 94.75.219.73.3740: UDP, length 92 21:18:02.859868 IP 94.210.218.46.38071 > 94.75.219.73.3740: UDP, length 92 21:19:02.979885 IP 94.210.218.46.39532 > 94.75.219.73.3740: UDP, length 92 21:20:03.099878 IP 94.210.218.46.51810 > 94.75.219.73.3740: UDP, length 92 I'm using a UBNT Edgemax Lite router tunnel tun0 { address 2001:1af8:fe00:461::2/64 encapsulation sit local-ip 94.210.218.46 mtu 1280 multicast disable remote-ip 94.75.219.73 ttl 255 } protocols { static { interface-route6 ::/0 { next-hop-interface tun0 { } } } } The firewall is disabled for the time being (to eliminate fw issues). S>* 0.0.0.0/0 [210/0] via 94.210.218.1, eth0.400 C>* 94.210.218.0/23 is directly connected, eth0.400 C>* 127.0.0.0/8 is directly connected, lo C>* 192.168.21.0/24 is directly connected, eth0.10 S>* 192.168.22.0/24 [1/0] via 192.168.21.254, eth0.10 C>* 212.121.121.128/32 is directly connected, pppoe0 S>* ::/0 [1/0] is directly connected, tun0 C>* ::1/128 is directly connected, lo C>* 2001:1af8:fe00:461::/64 is directly connected, tun0 C>* 2001:1af8:fe00:8461::/64 is directly connected, eth0.400 C * fe80::/64 is directly connected, eth0.400 C * fe80::/64 is directly connected, eth0.10 C * fe80::/64 is directly connected, eth1 C>* fe80::/64 is directly connected, eth0 C>* fe80::5ed2:da2e/128 is directly connected, tun0 traceroute to 94.75.219.73 (94.75.219.73), 30 hops max, 38 byte packets 1 5ED2DA01.cm-7-3d.dynamic.ziggo.nl (94.210.218.1) 9.126 ms 9.265 ms 9.085 ms 2 mnd-rc0001-cr101-ae15-230.core.as9143.net (213.51.165.153) 6.362 ms 103.382 ms 8.315 ms 3 asd-tr0042-cr101-ae7-0.core.as9143.net (213.51.158.2) 10.349 ms 8.285 ms 7.915 ms 4 leaseweb.evoswitch.nl-ix.net (193.239.116.221) 11.837 ms 10.112 ms 10.825 ms 5 85.17.100.37 (85.17.100.37) 10.966 ms 11.661 ms 11.921 ms 6 evo-hv5-te-2-3.evo.leaseweb.net (94.75.219.249) 11.095 ms hv5 (94.75.219.251) 9.220 ms 94.75.219.253 (94.75.219.253) 9.136 ms 7 nlhaa01.sixxs.net (94.75.219.73) 16.937 ms 16.597 ms 7.804 ms Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down Interface IP Address S/L Description --------- ---------- --- ----------- eth0 - u/u eth0.10 192.168.21.245/24 u/u data eth0.400 94.210.218.46/23 u/u 2001:1af8:fe00:8461::1/64 eth1 - u/u eth2 - u/D lo 127.0.0.1/8 u/u ::1/128 pppoe0 89.146.28.141 u/u tun0 2001:1af8:fe00:461::2/64 u/u Heartbeat script: #!/usr/bin/python # import time,hashlib,subprocess,socket,os localv6="2001:1af8:fe00:461::2/64" password="xxxxxxxxxxxxxxxxxxxx" remotev4="94.75.219.73" remotev6="2001:1af8:fe00:461::1/64" while 1: hbBase="HEARTBEAT TUNNEL " + localv6 + " sender " + str(int(time.time())) hbToSend=hbBase + " " + hashlib.md5(hbBase + " " + password).hexdigest() sock = socket.socket(socket.AF_INET,socket.SOCK_DGRAM) sock.sendto(hbToSend, (remotev4, 3740)) sock.close() with open(os.devnull, "w") as fnull: subprocess.call(["/bin/ping6", "-s", "8", "-c", "1", "-q", remotev6], stdout=fnull, stderr=fnul time.sleep(60) Somebody some hints, tips or suggestions?