Question : Problem: netopia modem with dsl to sonicwall

upgraded to sonicwall 2040 with enhanced os and a T1
want to use old dsl line with netopia modem for bandwdith and isp connectivity failover

Just want to check the best way to do this.

I was thinking to Leave the netopia modem/router as gateway and create DMZ that directs one of our dsl IPS (we have 5) to the sonicwall

The alternative is to disable the gateway on the netopia and route to the sonicwall. Not sure how to do that though.

Any advice?

Answer : Problem: netopia modem with dsl to sonicwall

I'm assuming you want your Sonicwall to be the primary gateway for your network. That said, REIP the inside interface of the sonicwall to the same gateway interface as the netopia so that way you don't have to change any routing information for the devices behind your sonicwall.

Then REIP your router to a different IP. You can then probably set up failover on the sonicwall to route traffic to the your netopia if the outside fails for some reason.

I don't see a point in DMZ'ing one IP and creating an extra hop in your routing table unless you need to do it for a specific reason.