PPTP
Point-to-Point Tunneling Protocol (PPTP) allows single Internet-based hosts to access internal network services through an encrypted tunnel. PPTP is easy to configure and requires no special client software on Microsoft Windows systems.
PPTP is included with versions of Microsoft Windows starting with Windows 95. In order to use PPTP with Sophos UTM, the client computer must support the MSCHAPv2 authentication protocol. Windows 95 and 98 users must apply an update to their systems in order to support this protocol.