This question comes from a security aspect rather than a routing/network aspect (which is why I chose here instead of server fault).
We are creating a network architecture and have 2 webservers. One of the web servers has access to a very sensitive database (in the "database layer") with an entirely different risk assessment. On a scale of 1-10, this data is a 7. The other web server has meaningless data, a 2/10.
An associate of mine believes that because both are web servers, and because they both allow port 443,80, they should be placed in the same network. They believe that if we set a policy (web servers in insecure zone), all web servers that meet this "policy" should be placed in the same network. I don't agree with this approach. We have tons of address space so why not throw the meaningless web server and its database in a separate network? I understand it is important to define a model for your architecture, i.e. "insecure network","database layer", application layer". But I challenge that just because two servers are a web server, does not necessarily mean they should be in contact with each other. Sure we could implement host based firewall and clever routing, but WHY... I'm worried that if a breach does happen to the meaningless web server, the attacker could, theoretically, obtain access to the very sensitive web server.
I'm not looking for who is right, because I see both sides.
My question is that if two servers are running the same software (web server), should they be placed in the same network, given that they require access to information that is on different (for lack of a better term) threat levels?