[KLUG Members] Routing issue

[John Pesce]

Ok maybe this is clearer :)

I have a linux box sitting between two subnets.
I have a subnet 192.168.3.0/24 connected to eth0 with IP  192.168.3.1.
I have a subnet 192.168.2.0/24 connected to eth1 with IP  192.168.2.1.
I have IP forwarding turned on and TCP traffic flows between them.

I need to connect to a new dedicated T1 with a Cisco router/CSU/DSU at 
each end that I have no control over. I am presented with an ethernet port 
on the Cisco with an address of 10.7.35.1

On the other end of the T1 are five subnets that I don't have control of.
They are somehow patched together with Cisco routers and T1s as well.
All the Cisco routers have dense mode multicast enabled.
The remote subnets are 10.7.31.0/24, 10.7.32.0/24, 10.7.33.0/24, 
10.7.34.0/24, 10.7.36.0/24

My thought is to put a third NIC card in the linux box and make that 
interface 10.7.35.2. Then add some static routes to direct the flow.

> Doesn't the router have an ethernet port?  That would reduce a hop.

Lost me. Yes it has an ethernet port with an address of 10.7.35.1
I need to plug an ethernet cable into it going somewhere, so I assume into 
the third NIC so the packets can be routed through the linux box with 
IPtables retricting access to my LAN.

At each of the remote five LANs and on my local LAN are linux boxes 
running a multicast application that connects to the same multicast group 
as a kind of n-way party line.

How do I patch this Cisco to my linux box that sits between my two 
existing LANs?


Thanks all