I got a problem configuring my company network. The situation is difficult because there are 2 companies with two ISP connections but using the same file server. No security or administrative tool was involved until now, only two subnets and two Win workgroups were used. I would like to introduce a DC (one AD for the two companies, because they are connected in business and have the same owner) and I would like to configure the two companies to use the two different ISP services. How should I configure the network? My idea is that I will create (actually it's already done) two subnets with to default gateways and each connects to a LAN port of the DC. The problem I found that the second subnet simply can't find the DC, at least the DNS does not work. How should I configure my DNS or how should I reconfigure my whole network? Thank you for the suggestions.