You missunderstood me. I do use the heartbeat program inside the script. The problem is that my IP only changes if I leave my computer off for some hours. It does not change elsewhere. What the script does is just create the tunnel, detect the IPv4 address and create the tunnel. After that, it calls the heartbeat program and does nothing more... it's obvious that when I boot into linux, I gotta bring up the tunnel manually (that's what the script does, nothing more)... what's the problem with that? Please, check and tell me which is the offending line so I understand what you mean (I followed the Gentoo guide, as you suggested): IPv6_interface="eth0" IPv6_popserver="<not shown>" (The IPv4 POP server address) IPv6_addr="<not shown>" (The IPv6 address I was assigned) my_ip=$(/sbin/ifconfig | /bin/grep ${IPv6_interface} -A 1 | /bin/grep "inet addr" | /bin/tr ' ' '\n' | /bin/grep "addr" | /bin/cut -b 6-); /sbin/ip tunnel add sixbone mode sit remote ${IPv6_popserver} local ${my_ip} ttl 64 dev ${IPv6_interface} /sbin/ip link set sixbone mtu 1280 /sbin/ip link set sixbone up /sbin/ip addr add ${IPv6_addr} dev sixbone /sbin/ip route add 2000::/3 dev sixbone /usr/bin/heartbeat-client /etc/sixxs-heartbeat.conf