I'm using a SonicWall NSA 240 which has two WAN ports (T1 and Comcast) and the LAN port has a cable which connects to a switch. From the switch, several cables connect to other switches. The SonicWall doesn't have DHCP enabled; one of our domain controllers running Windows Server 2003 also functions as a DHCP server.

Is there a way for a user in our network to change connection from T1 to Comcast as their ISP or vice versa? In other words, if a user is connected via the T1, can he/she somehow connect via Comcast instead? Thanks, in advance, for your help!

Sincerely, Charles

2 Answers 2


I don't use Sonicwall but I doubt the user can specify at their end which WAN to use. You can probably set up a 1-to-1 outbound NAT for the user's IP (will want them to use a static IP) in the firewall to go out one or the other WAN though.

You can also probably set the Sonicwall to be in either Failover WAN mode (all outbound traffic routes out one of the WANs unless it goes down, then routes all traffic out the other) or Dual-WAN mode (traffic can go out of either WAN connection and the firewall arbitrarily chooses which one). You might try setting the Sonicwall up in Failover Mode and route all traffic out the Comcast connection, but this will affect ALL outbound traffic, not just certain users. If you want to pick and choose users, you will likely have to go the 1-to-1 NAT route...


I don't recall the model number offhand, but we had a Sonicwall setup to do exactly what you're looking to do... or close enough for hand grenades anyway. There was a balancing setting (somewhere in the management interface, sorry, I don't remember precisely) that said "as soon as the bandwidth on this connection is X% used, start sending traffic over to the 2nd connection."

We set it to 10%, basically saying that once the T1 started to get a bit of traffic, everything should be routed to the Comcast line. Generally the servers kept the T1 busy enough that the users & their web browsing always ended up on the cable.

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