Multiple WAN interfaces in same subnet on Sonicwall NSA220?

Question

(eta salutation, which keeps getting eaten.)

Hi, all.

I see a bunch of related questions, so I'm hesitant to ask, but:

I have a situation where I have a Sonicwall NSA220 serving as firewall/router for two internal subnets to two external WAN connections. In some locations this is two separate ISPs. In others, it's the same ISP but with multiple circuits.

The problem is that one ISP has been unable to provide unique subnets for each WAN interface.

Is there any possibility that I might be able to bond the two WAN interfaces into a single virtual interface, and then use source-routing to get internal subnets communicating out the appropriate physical interface? Or even just use traffic-shaping to give each internal network appropriate shared bandwidth? I haven't found anything in the docs, but it seemed like it might be worth asking.

Thanks for any help! -Steve.

Solution

You may try the following setup:

Install a switch in front of SW and connect two ISP connections from the same subnet).

ISP link 1------
                |--switch---|--sonicwall--|----LAN
ISP link 2 -----

On SW, assign a WAN IP from the same subnet.

Is WAN Gateway same for both Links?

If there are two, you may be able to setup two outbound routes for each Link.

Comments

[Ttamsen]

Thanks, but that's not quite the problem. I have multiple WAN IPs on separate interfaces. Since they're in the same subnet, one of the interfaces is not being brought up, with a "subnet already assigned to other interface" error. I was hoping I might be able to bond the two WAN interfaces somehow, although I see nothing in the docs that suggests it's possible. I'd be happy to be told I'm missing the blindingly obvious, though.

[Force Flow]

Try searching the SonicOS administrator's manual for WAN link aggrigation. You might have to contact sonicwall support about this one, though.