Single-Server Network

The single-server network is the most simple NetMail configuration because the NetMail messaging server is the only server in the Directory tree. This configuration is typically used by small to medium organizations that do not use eDirectory for other network services.

This system is easy to configure and manage; however, given there is only one messaging server, it has a single point of failure.

Multiple Standalone Messaging Server LAN

A multiple standalone messaging server LAN is a network with multiple messaging servers, but each messaging server has its own Internet domain name---that is, the users serviced by each messaging server receive messages at a unique domain. This configuration is typically used by medium to large organizations that have several, separately managed IS departments and Internet domains or subdomains.

This system is more complex to configure and manage than a single messaging server LAN. You must ensure that each messaging server is assigned the correct user contexts and Internet domains; and that it has local access to its associated objects. Although there are multiple messaging servers, each server functions as an independent messaging system; therefore, each server is still a single point of failure.

Multiple Messaging Server WAN

A multiple messaging server WAN is a network in which the messaging system connects different geographical locations, but users still receive messages at the same Internet domain. This configuration is typically used by government and enterprise organizations that have one or more remote locations.

This system is typically heterogeneous; it can include both standalone and distributed messaging servers. Consequently, it is the most complicated system to design and manage. Standalone messaging servers present a single point of failure for their associated user contexts; however, distributed messaging servers can be designed to provide load balancing and fault tolerance for their associated user contexts.