[nos-bbs] Virtual Machine Network Driver

Barry Siegfried k2mf at nnj.k2mf.ampr.org
Wed Sep 27 02:53:52 EDT 2006

[From: wa7nwp <wa7nwp at jnos.org> wrote]:

> The biggest problem with JNOS on Windows is that there's no easy and
> good connectivity between JNOS and the Windows system - like we get
> with Maiko's TUN0 or a virtual tty on Linux.   All the other virtual
> drivers have issues.  The only real solution is a second hardware
> network card and that defeats my idea of a clean and simple virtual
> machine that can be cut and pasted between systems.  VMware or Virtual
> PC may both work but that depends on how the networking and serial
> ports are handled.
> I would love to hear if anybody has tried and had success with a JNOS
> on Linux on windows under either VMware or VPC...

I have not tried NOS in a Linux VPC window but I have tried it in a
DOS VPC window and yes, it works fine.  I am no fan of Microsoft or
its products but VPC happens to be one incredible piece of software
and it does something very magical with regard to how it handles
ethernet NIC sharing between itself and the parent windows operating
system (as well as OTHER VPC windows in the same machine).

Unlike SwsVpkt, which causes an IP connectivity issue between itself
and the parent windows operating system because it shares the same
ethernet NIC (and MAC address), VPC actually somehow CHANGES the
MAC address it sees for the SAME ethernet NIC!  And if you put
multiple VPC windows in the same machine, each one can share the
same ethernet NIC and will get a different MAC address!  This
means that there are absolutely no IP connectivity issues between
the parent windows operating system and its VPC windows.

If you are interested in just how VPC accomplishes this MAC address
change, the best description I have found is the follow blog post
made by one of the guys working on VPC at Microsoft:


I had always assumed that MAC addresses are written in stone on the
NIC.  Apparently, they aren't, and even on most older NICs you can
send out packets with a user defined MAC address.  As a matter of
fact, the friend of mine who introduced me to VPC has also told me
that he has used 'ifconfig' in Linux to change a MAC address on
several occasions to force IP address changes from his provider
and he also tells me that in windows most ethernet NIC drivers
will allow you to enter any MAC address you wish.

This was all astonishing info I never knew!  It's too bad SwsVpkt
(which I actually prefer to use over VPC because of its simplicity)
won't allow us to do that.  :(

But the above information brings to my mind that it COULD be
possible to change an ethernet adaptor address from NOS, presuming
that NOS gave us the ability to do that which means that we might
be able to do it through SwsVpkt as well.  I have to give that a
whirl and see if it can be done.

But back to VPC, if you decide to install VPC you will want to
follow the directions for adding the "extensions", which gives
you things like file-sharing with the parent operating system and
being able to move your mouse between the VPC window and the parent
operating system without having to left click to get into or escape
via keyboard to get out of the VPC window.

73, de Barry, K2MF >>
          <|>      Barry Siegfried
| Internet | bgs at mfnos.net              |
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