Postfix - Postfix is a mail transfer agent (MTA) that routes and delivers electronic mail.
Thexyz - Secure premium email service with mobile sync apps for calendar, contacts, tasks, notes and FISMA compliant email archiving.
sSMTP - sSMTP is a simple MTA to deliver mail from a computer to a mail server.
ZixArchive - ZixArchive is a cloud-based solution to collect, store and search archived emails.
OpenSMTPD - OpenSMTPD is a FREE implementation of the server-side SMTP protocol as defined by RFC 5321, with...
Cryoserver - Cryoserver is an all-in-one email archiving solution that empowers you to preserve your email in a tamper-evident archive, making you transform your data into a useful archive for everyday use.