Routed setup and ARP issues

[Christian Lerrahn <lists%penpal4u.net@localhost>]

Hi,
I'm trying to setup a routed configuration of XEN. My ISP does not let
me use bridged setups and bans the use of MAC addresses other than the
one of the physical interface on the network.

There are 2 problems I have. One is that on Linux you need to use the
kernel's arp_proxy which I don't think the NetBSD kernel has on board.
Therefore I assume I need to set up a userland ARP proxy for the routed
setup to work. Am I right?

The second problem is how I make sure that the MAC addresses of the
virtual servers never make it onto the physical network. In other
words, I would like them to be able to communicate internally based on
their MAC addresses while at the same time all outgoing traffic
pretends that the physical device has all the IP addresses directly
assigned to it.

I'm wondering if this requirement actually means that my physical
network interface needs to have all used IP addresses as aliases.
However, while I could still route that, it seems like a bit of a messy
setup.

Has anyone ever set this up? Is there maybe a howto that I missed in my
web searches?

Cheers,
Christian