In this chapter, you will learn the following:
• Ideal configurations for common and uncommon scenarios
• Recommendations on policy, filtering, and actions
• Architectures to suit a variety of different organizations
This single book cannot provide recommendations for all possible challenges sent down to the messaging team. I do hope to provide enough guidance to build a reliable and resilient gateway security architecture that requires low administration day-to-day, but is flexible enough to deal with the changes in tactics by the bad guys and the changes in business requirements that affect email.
Ultimately, the goal of your ESA environment should be to have 100% uptime for gateway email ...