Re: gateway with one interface

[Bob <spam@homeurl.co.uk>]

Douglas A. Tutty wrote:
> On Sun, Oct 28, 2007 at 11:54:57AM +0500, meekaaku kaaku wrote:
>   
> > I have a small LAN with about 3 windows machiens, 1 debian server
> > (etch), and adsl router with 4 ports.
> > Currently, I am using the router as a gateway (192.168.0.1), and the
> > debian server is 192.168.0.254. The client machiens are configured to
> > use 192.168.0.1 as a gateway.
> >
> > What i need to do is to use the linux server 192.168.0.254 as a
> > gateway for all the client machines, thereby i can monitor traffic and
> > gives me more control. But the problem is the debian machine has only
> > one interface and it is not directly connected to internet. It is also
> > using the router  as the gateway to internet (just like the other
> > client machines).
> >
> > So my question is, can this be done? if so any pointers is
> > appreciated. I have checked routing/iptables info on the web, but in
> > all the cases, the linux machine is directly connected to the net and
> > has two interfaces.
> >     
>
> NICs are so cheap, just add a second one.  Sure, its possible, but to
> what end?  The packets will only flow through the debian box if
> everything else agrees to do so.  That will only happen untill something
> is rooted.  A dog off-lease responding to voice commands is not under
> controll but suggestion; neither when a squirrel runs by.
>
> Doug.
>   

Seconded, to make this work you need to have a switch that supports 
vlans, the one in your router probably does, so if you can get that to 
work you don't need to buy anything, however if you have to get one it 
will cost more than a new Ethernet card, I pick up nice 10/100 Mb/s 
(3Com, Intel, sis900, NOT Realtek though I gather their newer chipsets 
are better) secondhand for 5~10US.

Good luck.