🚀 go-pugleaf

You have three distinct issues:

1) physical network (ethernet)
2) logical network (TCP/IP)
3) packet forwarding (ipfwadm, or other methods)

It is best to not lump them together into a single larger problem.
Divide and conquer!

Ethernet does not care if multiple logical networks are using it, or
what protocols are used (IPX, IP, etc).

Ethernet also does not care if some machines on it's segment thinks
that it is 192.168.1.0 while others think that it is 207.1.2.3, etc.
But some routers and other devices on the segment might not like it.


On Fri, 21 Nov 1997 00:38:52 GMT, xenophon@linux.realideas.com
(xenophon) wrote:

>Ok, here is the scenario:
>
>I have a thinnet ethernet connection running from the wall to my
>Windows95 box.  In that win95 box is a combo card.  On the coaxial
>part of the card, I am running a coaxial cable from there to my linux
>box, and terminating the ends. Will this work?

There are only two terminators on a coax ethernet segment, one is
surely somewhere on the other side of the wall.

Here are basic rules regarding physically connecting coax ethernet:
Each coax network card has a "T" connector attached to it.
Each "T" connector has either two coax cables attached, or one coax
cable and a 50ohm terminator.

BNC ports on hubs are the same as those on stations, except that they
often have an "termination enabled" which I never use in preference
for an external terminator attached to a "T" connector.

You have the choice of using either BNC or UTP, not both, on a single
card.

> If so, what do I have
>to setup on both ends in order for the linux box to see the internet?
>Would I have to run the ethernet into the linux box first?  I only
>have one static ip address assigned to me.  If this will not work, how
>should I set this up if I use two separate ethernet cards in one box
>instead of the combo card.  (i.e. which box should have the two cards
>in it, and how should I setup the two system's network settings)

Since you have only one IP you have the following options:

1) Get another IP address assigned for your use
2) Use only one machine at a time
3) Use IP forwarding - (Linux box gets the IP).

For 3. you will have to setup a private TCP/IP network (192.168.x.x)
between Linux and one or more other machines (Win96/NT, whatever).

The first question is if two TCP/IP networks can reside on the same
physical network - YES.

The second question is if two IP numbers (different networks) can be
assigned to the same ethernet device in Linux - I think that this is
also a YES (not sure) - otherwise two network cards will be needed by
Linux.

Read the masquading HOW-TO and/or ipfwadm MAN pages to find out about
how Linux can foward IP packets to other machines.


Hope this provides some clearity.