Company ABC will test connecting networks with Company XYZ as part of their upcoming merger and are both concerned with minimizing security exposures to each others network throughout the test…

Creating a DMZ is a valid architectural control but requires prior knowledge of which traffic must traverse it; building the DMZ without defined data flows leads to misconfigured access rules.

Determining necessary data flows is the foundational step because it establishes the minimal set of communication paths the business actually requires between the two organizations. Without this analysis, any technical security control - whether a firewall, DMZ, or NIPS - would be configured without a clear baseline, risking either over-permissive rules that expose both networks or overly restrictive rules that block legitimate business traffic. This requirement-gathering step ensures all subsequent technical controls are correctly scoped and that each company's exposure is limited to only what the merger operationally demands.

Implementing a firewall for IPSec VPN traffic is a technical execution step that must follow the data flow analysis phase, as the firewall rules depend on knowing what traffic is permitted.

Deploying inline NIPS requires a baseline of expected traffic patterns to detect anomalies accurately; without defined data flows, the NIPS cannot be tuned and will generate excessive false positives.