Re: Converting between IPv4 and IPv6

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

Hubert Feyrer wrote:
> On Sat, 1 Mar 2008, Darren Reed wrote:
> > Something that I'm looking at now with IPFilter is converting IPv4 
> > headers
> > into IPv6 headers and back again as part of its NAT functionality.
>
> Um, I wouldn't expect Network Address Translation to also add protocol 
> translation... for that, I'd expect separate things like stf(4) or 
> faith(4).

So, what would the operational model be?

The network interface that is going to require two addresses:
- a destination for IPv4 traffic that comes in to be routed to
- a destination for IPv6 traffic that comes in to be routed to

But how do we control traffic?

One might say use the routing table, such that specific destinations
are routed at the IPv4 address of the interface and likewise for IPv6.

But as people are surely going to notice, this only allows selection
of packets based on the destination address when many may also
want to include the source address in that decision.  This is similar
to what is done with stf(4) today.

Next we need a completely new tool - unless ifconfig is going to
be enhanced - to manage a new configuration file, kernel configuration
bits, etc.

As much as I hate to say it, this is probably a better approach
to take and means ipfilter doesn't get cluttered with lots of crap
code.

Darren