Network Numbering Problem, 3-4 nics instead of Hub

[Ed K.]

On Wed, 13 Apr 2005, Johnny Smith wrote:
> Hallow all,
>
> I have a network numbering/routing question.
>
> I have a pretty standard home network with a linux
> firewall/NAT box feeding a
> hub to what is is usually 3-5 machines.
>
> Can I eliminate the hub and use 3+ nics on the
> firewall box and
> 'how' would I number them???
>
> I have set this up once before but I find that
> the various hosts connected to the firewall can not
> see or access each other, but all can access the net.
>
> what am I doing wrong below ?
>
> Internet==> firewall/NAT Machine [with multiple Nics
> and CrossOver CAbles to Hosts] ==>
>
> ==>  eth0  [ 10.0.0.1/255.0.0.0]  ==>
> host-1 eth0= 10.0.0.2/ 255.0.0.0
>
> ==>  eth1  [ 172.16.0.1/255.255.0.0] ==>
> host-2 eth0= 172.16.0.2/255.255.0.0
>
> ==>  eth2  [ 192.168.0.1/255.255.255.0] ==>
> host-3 eth0= 192.168.0.2/255.255.255.0
>
>
> The method above did now allow each host to see &
> access each other, they could access the internet.
>
>
>
> Could the following Alternative Numbering Work ??
>
> Internet==> firewall/NAT Machine
> [with multiple Nics and 'CrossOver Cables'
> to 'multiple' Hosts] ==>
>
> ==>  eth0  [ 172.16.0.1.255.255.0.0]  ==>
> host-1 eth0= 172.16.0.2/255.255.0.0
>
> ==>  eth1  [ 172.17.0.1.255.255.0.0]  ==>
> host-2 eth0= 172.17.0.2/255.255.0.0
>
> ==>  eth2  [ 172.18.0.1.255.255.0.0]  ==>
> host-3 eth0= 172.18.0.2/255.255.0.0
>
> Thanks in advance for any guidance you can give me.
>
> Johnny
>

I have a suggestion, use brctl http://bridge.sourceforge.net/howto.html

and bind eth0, eth1, and eth2 to the same logical device (br0) and then 
the three nics act like a three port bridge. You only configure one 
ethernet device (br0) for all three hardware ports.

ed