[TriLUG] OT: Bridge/Advanced routing

[John Turner]

On Jun 30, 2005, at 4:32 PM, 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

When I was looking at getting DSL and Cable I was going to use one of  
these

http://www.xincom.com/twr402.html (around $100)

They seem to have newer models, not sure about pricing.

If you only have a few machines on your local network you could do  
something with the routing table and virtual interfaces (I do this  
for VPN access from home), but it doesn't help with redundancy, it  
just lets me get to the Internet and work at the same time.

John