Mail essentials gateway deployment options There are a number of ways to install Mail essentials, and unfortunately it requires some thought prior to install Mail essentials which deployment options you will go for. Its best to deploy Mail essentials on a separate machine from the Mail server. If this is not possible, and you are using Exchange 2000, you can install Mail essentials on the Exchange Server 2000 machine. In this case, you can choose between 2 deployment options: Either create a second virtual smtp mail server for Mail essentials (called multiple IP mode), or install Mail essentials on the Exchange 2000 virtual server, in which case you can use Mail essentials for inbound security only (called inbound security only mode). More: Deployment option A: Installing Mail essentials on a separate machine (Inbound & Outbound security) Deployment option B: Installing Mail essentials on Exchange 2000 - inbound security mode (Inbound security only) Deployment option C: Installing Mail essentials on Exchange 2000 - multiple IP mode (Inbound & Outbound security) Which deployment option? Decision flow chart