[KLUG Members] Routing issue

[Rusty Yonkers]

> Ok maybe this is clearer :)
Yes it is ....

> 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.

At this point you are routing .... You do not need any static routes
or routing protocol since all the segments are directly connected....

> 
> I need to connect to a new dedicated T1 with a Cisco router/CSU/DSU
> at 
> each end that I have no control over. 

Since you do not have control over that the solution will have to be
a little more creative.  If you did have control you could replace
the Cisco router with a syncronis serial card in the Linux computer
to connect to the csu/dsu (i.e. something from Cyclades
http://www.genesys.ro/download/Networking/Cyclades/pc300.htm for
connectivity - just an fyi)

>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.

The third NIC makes sense.  As far as static routes .... since all
your segments are directly connected to the Linux box I believe that
the default gateway of the Linux box will be sufficient for routing. 
Just tell it a default route of 10.7.35.1 (assuming there are no
other routes out of the system). If you have another route out (like
to the Internet) you will have to put in static routes to the other
segments unless you can get the Linux box talking with the Cisco
boxes.
> 
> 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.

You can cable directly from the router to the nic card on the Linux
box but you will need to use a crossover cable to make a direct
connection since routers and computer nics are wired the same.  You
could get a cheap 5 port switch for about $20 and plug both into
that....  

> 
> 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.
> 

The multicast thing is the only thing that I am not sure on.  I am
just starting to learn that one myself.  I am not sure if the Ciscos
and Linux boxes will talk to one another.  If not, you could tunnel
the multicast traffic through the Cisco routers as if it were unicast
traffic.  I do know the Linux boxes are capable of that but am not
sure how to implement it.  :-(




=====
Rusty Yonkers
CNE, MCP, A+, CCNA, Linux+, Server+, Network+ certified
-----------------------------------------
Department of Redundancy Department
-----------------------------------------
Devoted RedHat fan... looking for penguin domination

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