Re: Correct method for IPv6 over IPv4 tunneling

[Darren Reed <darrenr%netbsd.org@localhost>]

Ignatios Souvatzis wrote:
> On Wed, May 16, 2012 at 09:34:11PM +1000, Darren Reed wrote:
> > On 16/05/2012 9:15 PM, Hubert Feyrer wrote:
> > > On Wed, 16 May 2012, Darren Reed wrote:
> > > > netbsd ~# ifconfig gif0 create
> > > > netbsd ~# ifconfig gif0 inet6 2001::1 2001::2 prefixlen 126
> > > > ifconfig: SIOCAIFADDR_IN6: Invalid argument
> > > ...
> > > > Is my NetBSD foo wrong or...?
> > > Maybe you need something like
> > >
> > >     ifconfig gif0 tunnel a.a.a.a. b.b.b.b
> > >
> > > between those two lines? See here for a working example (no more in operation):
> > >
> > >     http://www.feyrer.de/IPv6/netstart.local
> > The problem was I was missing "prefixlen 128".
> > I had tried other prefix lengths but to no avail.
> >
> > Without that, it is not possible to configure an IPv6 over IPv4
> > gif tunnel.
>
> Hm.  Let me check my @work tunnel startup scripts.
>
> create
> tunnel labIV-gw-outer labIV-gw-outer-remote
> inet6 fe80::1/64 up
> !/sbin/route add -inet6 2001:db8:0042:5040:: fe80::2%$int -prefixlen 60
>
> Hm...
>
> I think (but didn't look at the source) you'd need prefixlen 128 for 
> point to point addresses, and get a network otherwise.

I suppose that's what confused me. Doing this:

# ifconfig gif0 inet6 10::1 10::2

didn't default to a prefixlen of 128 and it just fails with
a non-specific error message. I'd argue that ifconfig
should use a prefixlen of 128 in such situations automatically
and not require it on the command line, yes?

Darren