Businesses are taking advantage of the benefits provided by virtualization and cloud computing to build flexible, agile, and cost-effective IT architecture. These elastic capabilities help companies compete by accelerating the delivery of internal and customer facing applications and services. Many companies are building enterprise architecture by combining legacy, multi-cloud and virtual environments. The critical security problem is that these new opportunities to align with business resulted in a co-mingled architecture which effectively eliminates a formal architectural perimeter. Based on interviews with boards of directors and executive leadership teams facing these new environments, we explored the question: How do we secure increasingly dynamic architecture amidst increasingly coordinated and sophisticated threats? Based on this qualitative analysis we describe a number of security, compliance, and risk-based approaches that are effectively being used. Critical approaches identified and presented include, a risk evaluation of new technologies analyzing how they are aligned to emerging threats and remediation. In addition, agile development, user behavioral analytics and automaton must be tied to a big data platform. Importantly, user-behavior analytics must be architected into all future design. In an environment without a perimeter, these solutions and lessons are critical for telecommunications companies, internet service providers, and public cloud hosting providers and decision-makers.