gateway for separate networks

[Bob Ababurko]

At 01:18 AM 9/12/2004 -0400, Charles Swiger wrote:
>On Sep 11, 2004, at 9:41 PM, Bob Ababurko wrote:
>>I have two networks that are routed to me via a serial connection, namely 
>>a T1.  I have just installed a new router and it has two ethernet ports 
>>that will route to the two different networks.  What I want to do is have 
>>a single machine have two routes to the Internet, but each NIC going 
>>through its respective network...one is a /24 and the other a /28.  So, i 
>>would think that this would require that "fancier setup", due to the fact 
>>that I want traffic going out each nic to go through its networks 
>>gateway.  Now, what is this fancier setup?
>
>Talk to your ISPs about setting up BGP peering.  This probably involves 
>getting an ASN from www.arin.net and a portable IP netblock.
>
>[ If you don't understand what I just said, ask your ISP. ]
>
>--
>-Chuck
   OK, I think that I need to make a few more points to make this 
clearer......sorry about that.  The two networks that I have are from the 
same ISP.  They get routed to me via the T1 and land on my serial 
port.  What I have then are two ethernet ports on my router(for a total of 
three, counting the serial for the T1 link), which are the gateways for the 
networks that I want to bring up.  Right now I have both of the networks up 
with machines attached which are passing traffic just fine.  What I want to 
do is use one machine to send and receive packets or traffic with two NICs 
connected to their respective networks instead of using two separate 
machines to do the duty.  It is a matter of telling the machine what to do 
with the traffic depending what network the traffic originated from.  So, 
if I want traffic to flow using the second NIC, I need to be able to tell 
the traffic to go out the second NIC to the gateway for that 
network.  Maybe, this is something that is just not possible, but I don't 
really see why it would be such a big deal, if traffic from a second NIC 
can traverse a plain old subnet.  I just need to add a gateway to that 
subnet!
   Ok, what I ultimately want to be able to do is send and receive email 
from both networks, as each of these network has a specific duty.  I am 
interested in this to cut down on hardware costs, and have not investigated 
this at the application level to even be able to say it is possible.  What 
I can do, is run another instance of the MTA if it comes down to it.

-Bob