PPTP (Point to Point Tunneling Protocol), the point-to-point tunneling protocol. This protocol is a new enhanced security protocol developed on the basis of PPP protocol. It supports multi-protocol Virtual Private Network (VPN), and can enhance security through Password Authentication Protocol (PAP), Extensible Authentication Protocol (EAP) and other methods. sex. Allows remote users to securely access the corporate network by dialing into the ISP, directly connecting to the Internet or other networks.
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Point-to-point tunneling protocol (PPTP) is a network technology that supports multi-protocol virtual private networks, and it works at the second layer. Through this protocol, remote users can securely access the corporate network through Microsoft Windows NT workstations, Windows XP, Windows 2000 and Windows 2003, Windows 7 operating systems and other systems equipped with point-to-point protocols, and can dial up to connect to the local ISP and connect to the Internet securely through the Internet. company network.
The PPTP protocol assumes a connected and available IP network between the PPTP client and the PPTP server. Therefore, if the PPTP client itself is already part of the IP network, it can connect to the PPTP server through the IP network; and if the PPTP client is not yet connected to the network, such as in the case of Internet dial-up users, the PPTP client must First dial the NAS to establish an IP connection. The PPTP client here refers to the VPN client using the PPTP protocol, and the PPTP server refers to the VPN server using the PPTP protocol.
PPTP can only be implemented through PAC and PNS, other systems do not need to know about PPTP. Dial-up networking can connect to a PAC without knowing PPTP. Standard PPP client software can continue to operate over the tunneled PPP link.
PPTP uses an extended version of GRE to transport user PPP packets. These enhancements allow low-level congestion control and flow control to be provided for tunnels carrying user data between PACs and PNSs. This mechanism allows efficient use of the available bandwidth of the tunnel and avoids unnecessary retransmissions and buffer overflows. PPTP does not specify a specific algorithm for low-level control, but it does
define some communication parameters to support such algorithm work.
The PPTP control connection packet includes an IP header, a TCP header and PPTP control information.
When using VPN, you can use PPTP protocol or L2TP protocol. The specific setting method is as follows: For example, in Windows XP, first, right-click a VPN connection in the "Network Connection" window and select "Properties". Next, select the "Network" tab in the properties window that opens. Then select "PPTPVPN" in "VPN Type", and click the "OK" button.