I have a LAN that will host an EXTRANET site with 5 servers, and 2 exchange edge servers. The LAN will service an office in a 5 story building with about 100-200 users on each floor. Each floor will have it's own set of switches in supply closets.
After the initial deployment, we expect the amount of servers to grow. While examining some DMZ network maps, I noticed some of the models had just two firewalls. Others had 2 firewall solution including routers in both the private network and perimeter network.
What reason would a network want a router in the private network and inside the DMZ for the public facing servers? Does it provide any security benefit? I assume it would be a management benefit of some kind on a larger LAN. Another assumption I had on why a router would be in the DMZ would be if the server only had a single NIC, or if you had many servers that provided very distinct services and you wanted to logically divide them for management purposes?
Local area network containing DMZ and routers