[TriLUG] OT: Bridge/Advanced routing

[Jon Carnes]

I don't know exactly what you want but I set these types of scenarios
all the time.  I generally run two different private networks off of the
E0 and E1 interfaces respectfully. At that point it's trivial to set up
routing between the two networks. 

I would setup two default routes on the 2621: one that goes out the T1
interface and a second failover that points to the cable modem. If your
T1 goes down, then your traffic goes out the cable modem.  Of course
this only helps with your NAT-ted traffic and won't help with your
hosted services (though you could easily setup a secondary Mail address
that comes in via the cable modem).

I know some folks that actually bridge on these Cisco's and I've seen
some interesting setups for that - though in most cases routing should
work just fine.

good Luck - Jon Carnes
(BTW, OpenBSD would bridge these networks just fine... :-)

On Thu, 2005-06-30 at 16:32, Steve Hoffman wrote:
> 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