clanefco:~# ifconfig sit0 up
sit0: ERROR while getting interface flags: No such device
clanefco:~# ifconfig sit0 inet6 tunnel ::216.66.80.26
SIOGIFINDEX: No such device
clanefco:~# ifconfig sit1 up
sit1: ERROR while getting interface flags: No such device
clanefco:~# ifconfig sit1 inet6 add 2001:470:1f08:1b3f::2/64
SIOGIFINDEX: No such device
clanefco:~# route -A inet6 add ::/0 dev sit1
SIOGIFINDEX: No such device
OK, what OS?
debian-5.0-x86-default
have you seen this?
http://www.tunnelbroker.net/forums/index.php?topic=262.0
or
http://forum.linode.com/archive/o_t/t_1334/issue_with_ipv6_on_debian.html
Google is your friend