If you are referring to making a remote access VPN connection, almost any.  Titanium Mirror uses the Point to point tunneling protocol (PPTP) with mSCHAPv2 authentication and stateless MPPE encryption for remote access VPN connections from individual computers.  Our clients are currently using the following PC-class operating systems:

• Microsoft Windows (98, 2000, NT, XP)
• Macintosh MacOSX
• Linux (RedHat, Mandrake, Suse, etc.)
  

These and other personal computer operating systems provide a PPTP client that is compatible with Titanium Mirror internetwork appliances.