How can I design this network (two internet connections)

[fyouelaine]

Hello:

I have four computers that I need connected to a network.  These computers need to communicate and ping with each other.

I need computers 1 and 2 to always be connected to my Cable ISP and I need computers 3 and 4 always connected to my DSL ISP.  I don't want the ISP's to move back and forth between all four computers even if one ISP is down.

I have tried the following:

Connected computers 1 and 2 to cable ISP and 3 and 4 to DSL ISP.  I also connected them both to an unmanaged Netgear switch.  I'm using static IP's for all four computers on the same gateway (192.168.0.1).  The networking part is fine but the ISP's jump around to the different computers.

I don't really understand networks - so any help would be appreciated.  Do I need new hardware or do I need to adjust the gateway(s) or Subnet?

thanks

[icecream-guy]

you should have 2 seperate networks and using a router to route between  networks

[deanwebb]

And that router needs to be set up so that the ONLY outbound routes for 1 and 2 are to the Cable ISP and the ONLY outbound routes for 3 and 4 are the DSL ISP. I'd add in also that all inbound traffic from the "wrong" connection should be dropped at the router, since you don't want it to come in.

Now, the design question... why do they get to talk to each other but have to use different ISPs? If it's a matter of load sharing, there are link balancer products that would permit that without having to introduce a routing scheme for your 4-PC setup.

If this is a home office or small office (SOHO is the acronym that describes this market), then it may be that you could get a managed switch that allows you to do VLANs and Layer 3 functions, that's what you would look for in that product. But it needs to be a managed SOHO device, because there will be configuration elements that you will have to specify for it to function as desired.

[Otanx]

Ignoring why you would want to do this you should be able to setup one router with 192.168.0.1 then set the other to 192.168.0.2. Set every machine with a static IP, and assign the gateway IP based on which link you want them to use going outbound. All the systems can talk to each other, but will only use the gateway you configured to go out. If you want to swap a system you update the gateway to point to the other IP.

-Otanx

[deanwebb]

I'm doing my Palo certs and I can think of a GREAT solution for this involving an HA pair of PA-7000s in Virtual Wire mode. May be a bit pricey for a home solution, but you'll certainly have peace of mind that all is running as it should.