Subject: Re: Tap(4) interface in NetBSD?
To: Andrew Brown <>
From: Andrew Gillham <>
List: current-users
Date: 04/27/2003 19:22:31
On Sun, Apr 27, 2003 at 03:45:14PM -0400, Andrew Brown wrote:
> >> i guess i must be wrong, but i presume that if i read from it, i get
> >> copies of all ethernet frames received by the host (which is somewhat
> >> like reading from an AF_INET, SOCK_RAW socket), but that doesn't seem
> >> of much utility to me.
> >
> >Think a simulator like SIMH-VAX. 
> right, i've used that, but that uses bpf.  because it has to.
> it also asserts its own ethernet address, so if the kernel didn't
> rewrite the source ethernet address when transmitting the packet
> (never mind deciding which interface on which to transmit it), and
> then rewrite it *back* when replies were received, it wouldn't help
> much.
> i don't think that's it.

Think about bridging non-IP ethernet frames over a VPN.
Presumably you could have a vtun (or other) VPN between tap0 on one box
and tap0 on another.  Enabling bridging with xyz0 / tap0 on either end
should give you an ethernet bridge over a VPN.

While it sounds disgusting it could be useful. :)