"Stalker Software's CommuniGate Pro is an affordable, robust,
cross-platform email server that supports nearly every mail
standard out there. I recently migrated a live CommuniGate Pro
installation from Windows NT 4.0 to Red Hat Linux 9 and improved my
client's messaging performance. The process wasn't difficult, but
if you're contemplating a similar migration, let me warn you about
a few things to watch out for.
"My client needed to upgrade his messaging because his Windows
NT-based server was a bit long in the tooth and straining under the
current demand for its services. Based mostly on cost and partly on
my recommendation, the organization chose not to upgrade to Windows
2000. Continuing to use Windows NT was not an option due to
Microsoft's choice to stop supporting the product.
"The cross platform nature of CommuniGate Pro is a virtue for
current and potential customers. The software runs natively on more
than 30 OS and platform combinations ranging from Windows 95 to IBM
OS/400. An issue tied closely with platform compatibility is
scaleability. CommuniGate Pro, through clustering, can scale to
millions of user accounts. A German company uses CommuniGate Pro to
service over 4.5 million customers...""