Re: 2.4.21+ - IPv6 over IPv4 tunneling b0rked

Mika Liljeberg
2003-07-11T01:48:57Z

On Fri, 2003-07-11 at 04:49, Andre Tomt wrote:
> > Setting your tunnel prefix to /64 is certainly the right thing to do.
>
> If you don't have anything but one /64 for example.. I guess /126's
> would be ok as you could rule out the the anycast address? It will
> probably work with Linux - but is it wrong in any sense, other than
> "breaking" with EUI-64/autoconfiguration?

It doesn't really make sense to use a prefix longer then /64. The last
64 bits are generally reserved for interface ID.

What you can do, though, is not configure a link prefix for the tunnel
at all. I.e. you can add the local tunnel end-point as a /128. This
won't create an on-link route in the routing table, so you need to point
the default route to the interface rather than the peer end-point. For
example:

ifconfig sit0 add 3ffe:dead:beef::dead:beef/128
ip route add ::/0 dev sit0

Cheers,

MikaL