An Introduction to PPTP (Point-to-Point Tunneling Protocol)

What Is PPTP?

What is PPTP? PPTP stands for Point-to-Point Tunneling Protocol. PPTP is a network standard used to connect to a virtual private network or VPN. A VPN is a secure network that can be accessed via the Internet, allowing users to access the network from a remote location. This is very useful for users who need to connect to the office network from home or access the home computer from another location.

PPTP runs on TCP port 1723 and is one of the oldest VPN protocols still in use. It has existed since Windows 95 and is the standard for all Windows versions. PPTP was developed by Microsoft’s plan to encapsulate another protocol called PPP (Point-to-Point Protocol).

Among all VPN protocols, PPTP is one of the most common, the easiest to set up, and the fastest to calculate. For this reason, PPTP is very useful for speed-critical applications, such as audio or video streaming, and on older, slower devices with limited processors.

However, PPTP also has serious security vulnerabilities. Its underlying authentication protocol, usually MS-CHAP-v1/v2, is fundamentally insecure, and since PPTP was introduced, it has been cracked repeatedly in security analysis.

Advantages of PPTP

The following are the advantages of PPTP:

• Low management overhead: The administrator only manages the remote access server (RAS) and user accounts instead of managing different hardware configurations.
• Reduce hardware costs: Allow the ISDN card and modem to be separated from the RAS server, thereby reducing the purchase and management of equipment.
• Enhanced security: PPTP connections are encrypted and protected over the Internet and used with other network protocols, such as IP, Internetwork Packet Exchange (IPX), and NetBIOS Extended User Interface (NetBEUI).
• Reduce transmission costs: Except for the Internet, no other services are used.

How Does PPTP Work

How does PPTP work? PPTP is a product of PPP, therefore, based on its authentication and encryption framework. Like all tunneling technologies, Point-to-Point Tunneling Protocol encapsulates data packets to create tunnels for data to flow through the IP network.

PPTP uses a client-server design (technical specifications included in Internet RFC 2637), which runs on layer 2 of the OSI model. Once the VPN tunnel is established, PPTP supports two types of information flow:

1. Control messages are used to manage and ultimately disconnect the VPN connection. Control messages are passed directly between the VPN client and the server.
2. Data packets passing through the tunnel, that is, data packets to or from the VPN client.

Users usually get the PPTP VPN server address information from their server administrator. The connection string can be the server name or IP address.

Supported Tunneling Modes

The protocol supports two types of tunnels:

• Voluntary tunnel: A tunnel initiated by the client over an existing connection with the server.
• Mandatory tunnel: A tunnel initiated by the PPTP server of the ISP, which requires the remote access server to create the tunnel.

Three things are required to dial into an ISP that supports PPTP:

1. Your ISP must actually provide PPTP service to users, and it must be enabled for your account.
2. The network with which you want to establish a VPN must have a Window NT 4.0 RAS server with PPTP enabled. “Enable PPTP” means that the PPTP protocol is installed and the VPN dial-up port is set in RAS. The server must also be accessible from the Internet.
3. Your ISP must use a remote access switch that supports PPTP, such as Ascend MAX 4000 series or US Robotics Total Control Enterprise Network Hub. (These two products together constitute a large part of the ISP dial-up hardware market.)

Final Words

Here is all information about PPTP. You can know the definition, advantages, work principles of it. I hope that this post can be useful to you.