:nice: Hi guys, I have some problem about my testbed on tunneling. First and foremost, I am a newbie of FreeBSD and already familiar with Ubuntu. Currently, I need to build 6to4 tunnel. Both of them are going to be routers. So, this is an example source code of 6to4 tunnel in terms of different OS: Linux # ip -4 addr show dev eth0 3: eth0: <BROADCATS, MULTICAST, UP, LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 100 inet 184.108.40.206/24 brd 220.127.116.11/24 scope global eth0 # ip tunnel add tun6to4 mode sit remote any local 18.104.22.168 # ip link set dev tun6to4 mtu 1472 up # ip link show dev tun6to4 8: tun6to4@NONE: <NOARP, UP, LOWER_UP> mtu 1472 qdisc noqueue link/sit 22.214.171.124 brd 0.0.0.0 #ifconfig tun6to4 tun6to4 Link encap: IPv6-in-IPv4 inet6 addr: 2002:CBD3:4FC::1/64 scope: Global inet6 addr: ::126.96.36.199/128 Scope: Compat UP RUNNING NOARP MTU:1472 Metric:1 RX packets:0 errors:0 dropped:0 overrund:0 frame:0 TX packets:0 errors:0 dropped:0 overrund:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Problems: 1) After I create the tunnel interface in Ubuntu and restart the network, why the network interface configure to ignore the unknown interface tun6to4=tun6to4 ? From my research, to create the tunnel it doesn’t mention about NIC and commonly the NIC familiar with this interface only like eth0, eth1, lo and etc. Is there any installation for creating other interface in NIC for Ubuntu like tun6to4 ? 2) Besides, I try to ping6 to routers of FreeBSD but the result always shows Destination unreachable: Address unreachable even I have added route and destination of the router it said no route to host. Never mind, I consider that part of FreeBSD doesn’t setup very well. So, I setup FreeBSD as below: FreeBSD # ifconfig stf0 create # ifconfig stf0 inet6 2002:CBD3:4F2C::2 prefix 64 alias # route add –inet6 default 2002:C058:6301:: #ifconfig stf0 stf0: flags=1 <UP> metric 0 mtu 1280 inet6 2002:4A01:623::2 prefixlen 64 nd6 options=3 <PERFORMNUD, ACCEPT_RTADVD> Problems: 1) For FreeBSD part, I have been setup completely the text editor and follow an instruction to create the tunnel with default router of anycast address which is 2002:C058:6301:: Why I can’t write that route to routing socket whereby network is unreachable? Is it because of the IP of host in different subnet? I don’t know why problem is coming from ping6 of 6to4 tunnel while to ping6 between router and host is working very well. 2) Do all the default router is related to kernel? There also some error on mounting /dev/acd0 on /dist: Input/output error: (5) after I sysinstall and why kind of problem actually? What should I do? Thank you.