Minimal HW configuration (1-20 users):
CPU 1GHz, 512 MB RAM, 40GB of free space for message store and backup
Recommended HW configuration (20-100 users):
CPU 2GHz, 2GB RAM, 160GB of free space for message store and backup
Recommended HW configuration (100+ users):
CPU 2.8GHz Dual Core, 4 GB RAM, 200GB+ of free space for message store and backup
Microsoft Windows
Windows 7
Windows Server 2008
Windows Server 2008 R2
Windows Vista (Business, Enterprise or Ultimate edition)
Windows Server 2003 (SP2)
Windows XP (SP3 or SP2)
Windows 2000 (SP4)
Linux
Red Hat Linux
Supported versions: Red Hat Enterprise Linux 4.8 and 5, CentOS 5.2-5.5
SUSE Linux
Supported versions: openSUSE 10.0-10.3, 11.0-11.1, SUSE Linux Enterprise 10 and 11