Armor - Armor offers cloud security through integrated managed cloud or managed security as a service for public cloud or private cloud.
ClearOS - A very good alternative for Windows Server, for free
Zix - Leader in email #security | Easy-to-use solutions for #encryption, DLP, #advancedthreatprotection, archiving and BYOD security | https://t.co/7V5jQ5UfAo
NethServer - NethServer is an operating system for Linux enthusiasts, designed for small offices and medium...
Microsoft BitLocker - BitLocker is a full disk encryption feature included with Windows Vista and later.
Univention Corporate Server - Univention Corporate Server UCS with Active Directory functions and App Center is the cost-efficient and popular successor to Microsoft's server solutions.