Several companies networks in parallel isolation (developer network, normal network users, management, etc) and how to secure them?

Question

Well so I want create multiple networks so that they exist in isolation from each other.

It aims to ensure that it: a) has no redundant hardware (mail exchange, infrastructure, etc only once for all networks, but safe with isolation) b) the networks do not threaten each other (a compromised network that will not affect the others have) c) an exchange of data between the networks to be possible.

How do I put on the best approach? The networks have indeed because of their functions different requirements (sensitive data, isolation, external access to web, etc.).

I thought about a lot of work with terminal servers or through static routes in a direction to ensure the safety to charge the external server is not compromised internal server?

What are alternatives? Is there a best-practice how to build a corporate network?

Answer 1

Agreeing with user34092's comment, you can almost set up what you want using firewalls with multiple interfaces. Creating separate networks and applying rules to allow certain traffic between networks/interfaces would probably be the best way to accomplish what you want.

Answer 2

If you are transferring data between the networks, by definition they threaten each other. The only completely secure network is one that's in complete isolation.