Multitier topology gives you flexibility to segment resources based on role and access policies. In a typical three-layer application, architecture that has web, app, and DB servers can be distributed based on location. Since web/app zone is something always exposed to end users, Demilitarized Zone (DMZ) IP space is always public. Subnet and database servers should not be directly accessible, hence why we should always allocate private IP space from RFC 1918.
This offers gradual access to control, based on IPs and resource locations. When designing a network, you can introduce a multi-layer firewall approach. In a multiple ...
