Virtual Private Networks (VPNs) : A Survey

This paper is a survey on Virtual Private Networks (VPNs). The functionality of a VPN is precisely the same as any other private network. This means that information passed between parties on the network is protected from attackers. The difference between a VPN and another private network is that the former operates over a public network, such as the Internet. The VPN occupies its own private address space on the public network, thus making it inaccessible from the other users on that network. Also, the information in transit is encrypted so that if the data is intercepted, the attacker is not able to read it. Security elements such as confidentiality, authenticity and data integrity can be provided with these VPNs. These networks are attracting the attention of companies around the world for two reasons: they are inexpensive; and they are highly flexible. Many consulting firms, such as Aventail, and Eagle Systems are designing VPNs specifically to their customers needs depending on their security and performance requirements. Generally, in most VPN structures the higher the level of required security, the slower the system becomes. That fact that VPNs make use of a public network makes them highly cost-effective. With certain VPNs the companies requiring security facilities can make use of any Service Provider which will oblivious to the VPN it is hosting. Alternatively, the Service Provider can support the VPN so that the burden of the company having to maintain its own private network is lifted. In addition, if the company chooses to manage its own VPN, and does not lease the service from a Service Provider, the maintenance and administration on a VPN is considerably simpler than that on private leased lines. VPNs make use of many existing structures such as the virtual circuit and the security firewall. This paper will look at the structure of VPNs and the protocols that are implemented to control them. Its development, but the prospects for VPNs as a security structure on the Internet are very good. [10] This paper concerns the rise and development of the VPN. This new technology is one of the security industry's fastest growing products. It is difficult to find a suitable definition for the VPN. As we will see, the technology for implementing VPNs has been accessible for many years. However, it is only recently that various institutes have begun formalizing the VPN concept. As is usual in most fields of computer science many differing standards and protocols have been suggested, each one with their own definition of the VPN. Here, we will present a general definition for VPNs. The most generic definition of a VPN is that it is a temporary, secure IP connection over a public IP network, such as the Internet [2]. This connection has its traffic encrypted in such a way that only the source and destination can decrypt the packets. The VPN uses the same physical cabling, switches, bridges, and routers as the public network, but uses a different address space. This means that a publicly accessible network can be used for the transmission of confidential information. In this paper, we will examine the structure, security, and benefits of VPNs. We will also look at developing protocols on which VPNs are based. Firstly, though, we will look at the history and evolution of the VPN.