Service On the CD 

Zentyal Server 3.5 Community Edition, 64-bit

On the CD

Zentyal bills itself as "a drop-in replacement for Microsoft Small Business Server and Microsoft Exchange Server that you can set up in less than 30 minutes." According to the vendor, compatibility with Microsoft Active Directory and Exchange is so complete that small and medium businesses can migrate their systems transparently to Zentyal. Released under GPLv2, Zentyal Server 3.5 is based on Ubuntu 14.04 LTS and comes with a single LDAP implementation based on Samba 4.