PPTP or Point to Point Tunneling Protocol, is another method used to establish a VPN or virtual private network. It is an extension of the Point to Point Protocol (PPP). It was a popular choice when choosing a protocol for VPN because most platforms support it without any configuration. Support has dwindled on it though, because of security concerns regarding its encryption. To further elaborate on this, PPTP uses only DES encryption which can be cracked in under a days worth of computing due to only 2^56 possible key combinations. As a result of this, I will not go too deeply into this protocol further.