🚀 go-pugleaf

I need some help in setting up a firewall

I have installed Linux Slackware 3.4 on a 386 Dx 40 box and have the
two network cards operating . I have also subnetted a Class C address
with a netmask of 255.255.255.192 . 4 subnets ..

#1 xxx.xxx.xxx.1 - 63 - All the PC's are here and the internal
#2 xxx.xxx.xxx.64 - 127 - future reserved
#3 xxx.xxx.xxx.128 - 191 - future reserved
#4 xxx.xxx.xxx.192 - 255 - Where the external and router sit

I have enabled TCP/IP firewall , TCP/IP forwarding / gateway etc and
recompile the kernel 2.0.33 . I also have a router at xxx.xxx.xxx.254
. The two network cards have a address of .1 internally and .250
externally .. with a netmask of 255.255.255.192 right ?

The PC's are told the gateway is .1 . And a ping shows that it can
reach .1 and .250 . But it can not get to .254 (ISDN router) which has
a direct network cable link to the external interface.. 

Does the router need to know the netmask 255.255.255.192 or be
programmed with it ? 

What route command do I need to make the firewall box talk to the
router at .254 through the .250 (external interface) ? 

Better yet how I can I get it to route the packets destin for the
internet go through the external interface through router and out to
the internet . Do I need to create a static route to the down stream
router ( next router down ) ?

Or do I have this all wrong ? 

If anyone can help I would be grateful 

-- diagram --

PC's .2 - .63 --> int. gate .1 -> Ext. gate .250 -> router .254 ->
internet! (hopefully)

--  diagram --

Confused Admin
Daryl,