Hi, I have a working tunnel on my freebsd box, but can't get my other machines working. The network layout is simple: <INTERNET> ----- <ROUTER> ----- FreeBSD box on wired ethernet / some other devices in wifi Here is what I have (overview): - FreeBSD9 box, 2001:4dd0:ff00:1863::/64 subnet, running rtadvd, having an AYIYA tunnel at tun0 - BSD box can ping6 various services, e.g. www.google.de, so tunnel is working fine - Mac OSX box, correctly generating a 2001:4dd0:ff00:1863:... address and temporary address - OSX box is able to ping6 BSD with link local and public address of msk0 (local interface) - OSX box not able to ping6 BSD box IPs of tun0 interface - OSX box traceroute6 hangs on first hop - tcpdump on msk0 and tun0 shows packet comes in via msk0, forwarded via tun0 but no response I've got the feeling, I'm dancing around something obvious, but I don't get it - please give me a hint. Best, Thomas Here's some details: disabling bsd box firewall (ipfw) changes nothing routing table bsd box: Internet6: Destination Gateway Flags Netif Expire ::/96 ::1 UGRS lo0 => default 2001:4dd0:ff00:1863::1 UGS tun0 ::1 link#11 UH lo0 ::ffff:0.0.0.0/96 ::1 UGRS lo0 2001:4dd0:ff00:1863::/64 link#5 U msk0 2001:4dd0:ff00:1863::1 link#12 UH tun0 2001:4dd0:ff00:1863::2 link#12 UHS lo0 2001:4dd0:ff00:1863::3 link#5 UHS lo0 /* local stuff truncated */ tcpdump output: [root@zaphod /etc/rc.d]# tcpdump -i msk0 -i tun0 icmp6 tcpdump: WARNING: tun0: no IPv4 address assigned tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on tun0, link-type NULL (BSD loopback), capture size 65535 bytes 20:15:20.558624 IP6 2001:4dd0:ff00:1863:d429:7f23:54b3:8131 > bk-in-x5e.1e100.net: ICMP6, echo request, seq 0, length 16 20:15:21.562280 IP6 2001:4dd0:ff00:1863:d429:7f23:54b3:8131 > bk-in-x5e.1e100.net: ICMP6, echo request, seq 1, length 16 20:15:22.564537 IP6 2001:4dd0:ff00:1863:d429:7f23:54b3:8131 > bk-in-x5e.1e100.net: ICMP6, echo request, seq 2, length 16 20:15:23.565591 IP6 2001:4dd0:ff00:1863:d429:7f23:54b3:8131 > bk-in-x5e.1e100.net: ICMP6, echo request, seq 3, length 16 rtadvd.conf: msk0:addr="2001:4dd0:ff00:1863::":prefixlen#64: ifconfig on BSD box msk0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500 options=c019b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,TSO4,VLAN_HWTSO,LINKSTATE> ether 00:26:2d:04:c2:b4 inet6 fe80::226:2dff:fe04:c2b4%msk0 prefixlen 64 scopeid 0x5 inet6 2001:4dd0:ff00:1863::3 prefixlen 64 inet 192.168.1.101 netmask 0xffffff00 broadcast 192.168.1.255 nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL> media: Ethernet autoselect (100baseTX <full-duplex>) status: active tun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> metric 0 mtu 1280 options=80000<LINKSTATE> inet6 fe80::226:2dff:fe04:c2b4%tun0 prefixlen 64 scopeid 0xc inet6 fe80::4cd0:ff00:1863:2%tun0 prefixlen 64 scopeid 0xc inet6 2001:4dd0:ff00:1863::2 --> 2001:4dd0:ff00:1863::1 prefixlen 128 nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL> Opened by PID 2987 ifconfig on OSX en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500 ether 00:26:bb:06:8c:df inet6 fe80::226:bbff:fe06:8cdf%en1 prefixlen 64 scopeid 0x5 inet 192.168.1.142 netmask 0xffffff00 broadcast 192.168.1.255 inet6 2001:4dd0:ff00:1863:226:bbff:fe06:8cdf prefixlen 64 autoconf inet6 2001:4dd0:ff00:1863:d429:7f23:54b3:8131 prefixlen 64 autoconf temporary nd6 options=1<PERFORMNUD> media: autoselect status: active