In a heterogenous Open Systems network with UNIX, Linux and Windows servers, and/or workstations, the administrator is generally faced with the need to run several disparate e-mail systems. This is costly in terms of administration, maintenance and training for different user groups. There are also often problems in interfacing the different mail systems, because the functionality does not map one-to-one from one system to the next. Gallagher & Robertson e-mail is a single solution that runs on all the hardware and operating system platforms, and which offers the same rich functionality on each.

Gmail, the G&R e-mail system, is a single system offering clients that run on Windows, UNIX and Linux workstations and mail transfer agents that run on Windows, UNIX and Linux servers. A single Gmail 'post office' can be shared by clients on all platforms. A Gmail network can have post offices on all server types, and Gmail includes transfer agents that can move Gmail between post offices on disparate platforms. This simplifies the job of administration and day-to-day maintenance of the internal e-mail network. Gmail includes a seamless interface to Internet mail for exchanging mail with customers or business partners, and as much Gmail functionality as possible is mapped to Internet mail features where they exist.

The Gmail clients use a GUI on Windows workstations, and a full screen character mode display on UNIX/Linux, to give all users exactly the same rich functionality in a user-friendly fashion. The functionality offered to the users is at the very high level defined in the X.400 standard, and although the Internet standard (SMTP) has largely displaced X.400, the functionality defined in the X.400 standard is regarded as more advanced and functionally richer than that which Internet mail offers.

Gmail users enjoy full Gmail functionality across the internal Gmail network, even though it may include post offices on different platforms, widely spread across geographical locations. The Gmail transfer agents can use the Internet to move native Gmail between post offices, making Gmail as universally accessable as Internet mail.