lan problems

[Ronnie T Livingston]

Hi guys,  I was wondering if i could get some help with a LAN problem What
i am trying to do is use the static ip that was assigned to me and create
my own LAN using linuxmachine A as the both a firewall and a gateway.
Eventually id like to create a linux cluster where machine A will act as
a firewall and main server (sorry im not exactly sure what this machine is
called, i havent started on the linux clusters yet).

Now, I have machine A able to connect to the internet, it has monmothas
iptables script and it has 2 NIC cards.   I am trying to have the second
card connect with the machine B and eventually once it starts working i
would like to have computer A connect to a hub and have all the other
machines connect to machine A via the hub.  Initially i thought it may be
the firewall script but i disabled it and i still am not able to connect
to machine B.

I also know that the card is good, the hub and cables are good and
ipforwarding is enabled (see below):

$ cat /etc/sysctl.conf
# Disables packet forwarding
net.ipv4.ip_forward = 1
# Enables source route verification
net.ipv4.conf.all.rp_filter = 1
# Disables the magic-sysrq key
kernel.sysrq = 0

but still no interaction.

any help would be much appreciated,
Ronnie