PPTP vs. L2TP
PPTP is probably the most commonly used VPN protocol for establishing remote connections to a network from individual computers. It is also the older of the two protocols and it is most broadly supported among various operating systems (prior to Mac OS X 10.3, it was Mac OS X’s only native VPN protocol and it has been supported by several past versions of Windows). Although L2TP is newer, it is gaining ground because it does offer a more robust set of security options. In addition to being supported in Mac OS X for the past three years, built-in support for L2TP is included with Windows XP (earlier versions of Windows can access an L2TP VPN using a free client from Microsoft).