[TriLUG] OT: Bridge/Advanced routing

[Steve Hoffman]

I'm sorry to stray off topic here, but this could end up being on
topic in the end.  I've got a cisco 2621 router with a t1 card and two
ethernet ports running on a t1; additionally I have Time Warner
business class cable modem service.

We like to have at least two networks for redundancy (just in case)
but rather then one sitting idle all the time I'd like to create a
development network and a rest of the company network but bridge the
two so that requests for machines on one network or the other don't go
out to Atlanta and back when they could just as easily stay inside the
network.

I thought our cisco router would be able to do that just fine..but
apparently it can't route packets between interfaces...or I don't know
how to do it.


Here's how I envisioned it:


     T1                                 Cable Modem
      |                         z.z.z.z/28  |
      |  x.x.x.x/29                         |
      |  y.y.y.y/29                         |
--------------------                            |
| cisco 2621   |                           |  
---------------------                           |
e0|         e1 |_________________|
    |
    |
    |
----------------------
|       switches |
----------------------


the cable modem is locked down to the point that I can't add routes to
it...if I could I wouldn't be here right now...

Is there a device to bridge the networks since apparently the 2621
can't do it...or can the 2621 do it and I'm simply retarded.  Can I
put a linux box in there somewhere and use it to route between the two
networks?  I have no experience with xBSD so suggesting that won't go
far but if it's the only answer I'll put it on my list of stuff to
learn.

Any help or suggestions would be greatly appreciated.  

Steve