Check the system requirements for PureMessage for UNIX.

System requirements

• Platforms supported*
  32-bit RedHat Enterprise Linux on x86/x86-64 (3 to 4)
  64-bit Red Hat Enterprise Linux on x86-64 (AS/ES 4)
  32-bit SUSE Linux on x86/x86-64 (Enterprise Server 8 to 9, Professional 8 to 9.2)
  32-bit Debian on x86/x86-64 (3.0, 3.1)
  Sun Solaris on SPARC (8 to 10)
  32-bit FreeBSD on x86/x86-64 (5.3, 5.4, 6.1)
  *Run as a native operating system, or as a virtual operating system using VMWare ESX (for Linux) or Sun Solaris 10 containers (for Solaris).
   
• Gateway/email platforms
  Includes Sendmail: supports versions 8.11.6 or higher
  Includes Postfix: supports version 2.0.x and 2.1
  Supports Sun Java™ System Messaging Server 5.2 and 6 on Solaris
  Other email platforms: supported via relay configuration
   
• Memory
  Minimum: 1 GB
  Recommended: 2 GB
   
• Disk space
  200 MB plus quarantine space