I have 4 physically distinct networks. Let's call them A, B, C and D.
Usually, these should be isolated. However, there are various machines that require access to any two of them. These are secured with the necessary firewalls.
Now a requirement has come in that necessitates one machine having access to all 4 networks.
My initial reaction was to just put 4 NICs in the machine and be done with it, but this seems rather insecure. The recommendation from a previous installation is to use a switch to create a common network. Again, this doesn't seem secure. My question is this:
How would I implemente a network similar to the above diagram, where the router was a server and the 3 VLANS are my other networks. Such that:
- The server can access any machine on any other network according to that particular network's firewalls.
- Machines on the networks can access the server according to the applicable firewalls.
- There is no way for machines on the different networks to communicate with another network.
I'm not looking for a blow-by-blow, just for someone to point me in the right direction.