Today, more and more companies are moving to the cloud. It is estimated that almost half of enterprises are considering moving their IT infrastructures to the cloud. In the midst of enterprises looking to move to the cloud, their main concern is the security issues and risks involved. The majority of enterprises note these as their top concern and for good reason. The reality is that these moves represent both a challenge and an opportunity.
At first, it may seem as if moving your e-mail infrastructure to the cloud is a no-brainer, as the upkeep, capacity planning and troubleshooting becomes someone else's problem. However, the benefits outsourcing to the cloud offers brings risks that need to be carefully weighed for each portion of the e-mail infrastructure-before making a decision to keep it in-house or put it in the cloud. In the end, the most likely outcome is a hybrid infrastructure that makes use of both cloud services and in-house infrastructure.
E-mail infrastructure's three layers
Before we look at the benefits and risks of moving an e-mail infrastructure to the cloud, we need to define the three layers that make up a modern e-mail infrastructure. The first layer, the Gateway Layer (aka, the External Protection Layer), is found in the DMZ. This is where you typically find inbound malware (spam, viruses, etc) filtering, connection controls, reputation services, inbound verification [recipient validation, sender authentication via DomainKeys Identified Mail (DKIM), etc], simple routing, and security.
The second layer is the E-mail Backbone (aka, the Internal Layer) and it is typically found in the internal network. This layer performs bidirectional policy, directory-driven security, enforcement, and intelligent routing. It performs these duties by leveraging information in the enterprise directory and performing deep message inspection for outbound content policy to protect against leaking sensitive information. This layer is also likely the injection point for other applications in the enterprise that send outbound mail (for example, customer care, notifications, etc).
The third layer is the Mail Store Layer (aka, the Groupware Layer). Also found on the internal network, this layer encompasses the mail stores with simple policy and user-to-user message delivery. In large enterprises, there are often many solutions and servers in use, often geographically dispersed and sometimes segregated by business unit. It is the E-mail Backbone's job to properly route messages to the proper server in this situation.