There is a PPTP control connection between the IP address of the PPTP client using a dynamically allocated TCP port and the IP address of the PPTP server using the reserved TCP port 1723. The PPTP control connection carries the PPTP call control and management messages that are used to maintain the PPTP tunnel. This includes the transmission of periodic PPTP Echo-Request and PPTP Echo-Reply messages to detect a connectivity failure between the PPTP client and PPTP server. PPTP control connection packets consist of an IP header, a TCP header, a PPTP control message, and a data-link trailer and header as shown in the following figure:
Jump up ^ Cisco Systems, Inc. (2004). Internetworking Technologies Handbook. Networking Technology Series (4 ed.). Cisco Press. p. 233. ISBN 9781587051197. Retrieved 2013-02-15. [...] VPNs using dedicated circuits, such as Frame Relay [...] are sometimes called trusted VPNs, because customers trust that the network facilities operated by the service providers will not be compromised.
Another unique aspect of VyprVPN is that they offer a powerful obfuscation feature called the Chameleon Protocol. This is a self-developed OpenVPN protocol that obfuscates (hides) VPN traffic to appear like regular HTTPS traffic. The Chameleon Protocol allows you to use the VPN in locations where VPNs are normally blocked, such as in China, schools, libraries, work networks, and with some streaming services like BBC iPlayer.
One of the most popular VPN services in the market, HideMyAss has a myriad of features that are sure to attract anyone who wants online anonymity. It uses a variety of servers that work with any operating system or mobile device. Aside from PPTP and OpenVPN protocols, the service supports L2TP, which is more difficult to block. Ideal for getting around censorship and firewalls.
Are you so used to your data traveling over Wi-Fi that you've stopped worrying about the security of that data—and about who else might be spying on it, or even stealing it for nefarious purposes? If so, you are—sadly—in the majority, and you ought to consider using a viritual private network, or VPN. In fact, when PCMag conducted a survey on VPN usage, we found that a dismal 71 percent of the 1,000 respondents had never used a VPN. Even among those who support net neutrality—who you might think would tend to be well informed on technology and privacy issues—only 45 percent had used a VPN.