With the increasing popularity of the Internet, new technologies have introduced to provide secure access to the resources from remote clients. Virtual Private Networks are becoming the most universal method for remote access. They enable service provider to take advantage of the power of Internet by providing a private tunnel through the public cloud to realize cost savings and productivity enhancements from remote access applications. VPNs securely convey information across the Internet connection to remote users, branch offices and business partners into an extended corporate network. This paper is an attempt to provide an overview of VPN and its services and how the network security concerns are addressed. It begins by explaining the architecture and types of VPNs used. It then describes the various goals of VPN. Next it explains the basics of tunneling mechanism and how the various tunneling protocols can be used to provide secured communication over the public Internet. Further it compares the basic VPN architectures – MPLS- and IPSec-based VPN architecture. The paper concludes with a brief discussion of advantages and disadvantages of VPN and the essential attributes of the VPN architecture.
Key Words: Tunneling
The world has changed a lot in last few decades. The businesses now not only deal locally or regionally, but also think about global markets. They have spread out across the country or around the world and the main concern is to have fast, secure and reliable communication. The companies started using Wide Area Network (WAN) with leased lines to expand its private network beyond the immediate geographic area. Though the WANs with leased lines provided security, reliability and performance but it’s quite an expensive business to maintain it. The cost effective solution to this problem is Virtual Private Networks (VPN) which is an extension of private network to provide secure communication over large insecure network such as
Internet. VPN allows using public Internet to securely connect remote sites and employees at a fraction of cost of virtual circuits between hosts of larger network. VPN can greatly benefit the companies by extending geographical connectivity, reducing operational costs, improving productivity, simplifying network topology, reducing travelling costs of remote users and providing telecommuter support. VPNs maintain privacy through the use of security procedures and tunneling-mode protocols. The most commonly used security procedures in VPN is Encryption. The tunneling mode and security procedures ensure that only authorized users can access the network and data cannot be intercepted.
VPN message traffic is carried on public networking infrastructure e.g. the Internet, using standard protocols, or over a service provider's network providing VPN between the VPN customer and the VPN service provider. The main purpose of a VPN is to give the company the capabilities of having the same protected sharing of public resources for data as the private leased lines, but at a much lower cost by using the shared public infrastructure. The VPN connecting PC, remote sites and providing security measures is show below in Figure -1.
Figure – 1: Virtual Private Network
The common uses of VPN are discussed below –
Remote Access over the Internet – VPN provides remote access to corporate resources over the public internet, while maintaining the privacy of information. Rather than making a long distance call to a corporate or outsourced network access server (NAS), the user calls a local ISP. Using this connection, the VPN software creates a virtual private network using dial-up user and the corporate VPN server across Internet.
Connecting networks over the Internet – There are two methods for connecting LAN at remote sites – •Using a dedicated line to connect branch office to a corporate...