Splitting off internet access between 2 businesses

[2internets]

I have 2 internet connections on the same LAN. There are 2 businesses in the same building each with their own internet connection. These 2 businesses are all networked together so they can share files. There are a total of 7 computers (3 in one business and 4 in the other). I want the business with 3 computers to be using internet from 1 provider and the business with 4 computers to be using the other internet. I still want all computers to talk to each other though. I also have a simple file server which all computers need to access. I assume I would create a static route through one of the routers but am not familiar with that process. I have attached a link to a crude topology to hopefully display what the current setup is. Any help would be appreciated. Thank you.

https://ibb.co/nbskvw

 

[root]

So...
There are a few ways of doing this. Some more technical than others, depending on what you have setup so far.

The "easiest" way is with so few computers just give all the computers in business 1 a static IP you configure on the machines (e.g they are all 192.168.0.x with a subnet mask of 255.255.255.0 and point to 192.168.0.1 as their gateway.

Then give the computers in business 2 addresses 192.168.0.x addresses, same subnet (so they can all communicate with each other) but set their gateway to 192.168.0.2 so they use the other internet.

You could also set this up with DHCP reservations (if you have a DHCP server based on the individual computers MAC address.)


A much more complicated way would be to setup a network policy server and use 802.1x to assign different VLANs on a managed switch, that then got different VLAN numbers and therefore get information from a different DHCP scope allowing you to setup the gateway automatically based on machine name or active directory group membership, (also assuming you name machines according to a naming convention or have a common active directory setup.)

It seems strange that you'd have a business sharing a common local network, but using different internet connections...


Depending on what equipment is onsite. (I.e whether you have managed switches/firewalls/routers.) you could have business a use isp a and automatically fail over to ISP b if that failed. And business B use ISP B by default but automatically use ISP A is ISP b died... (But with so few machines you could just visit all the machines and manually change the gateway if that were to happen.)

If the second option sounds like gibberish, use the first! -but that is a lot of manual work setting the addresses manually, especially as the business grows.

 

[2internets]

I really appreciate your post. I got it working by putting 1 router gateway on 2.1 and the other on 2.200. I then assigned 3 computers with the 2.1 gateway and the other 4 on the 2.200 gateway. I didn't realize you could put 2 routers on the same subnet without conflict. Thank you for your response. I appreciate it.