The device at the end of any virtual private network connection is not necessarily a special VPN concentrator or router. What might come as a surprise, an ordinary personal computer is more than enough, provided that it is equipped with an appropriate operating system, and has VPN software.

Operating systems or software are most frequently applied to support virtual private networks in host-to-host or host-to-gateway architecture. It is quite uncommon for a personal computer to be used as a VPN server (or: VPN gateway). Yet, thanks to all possibilities opened up by personal computers, users who connect remotely to their, e.g., corporate networks, do not need special equipment - good software is all they need. The processing power of today's processors is enough to encrypt and decrypt user data.

Let us have a look at some of the most popular tools used in the area!

IPSec VPN

Available for all types of operating systems, IPSec is a protocol suite for implementing secure connections and encryption keys exchange between computers. It is one of the easiest and safest solutions to set up a VPN. IPSec VPN uses commonly accepted cryptographic algorithms: DES, 3DES, AES, RC4, and ensures data integrity through MD5 and SHA.

Windows VPN Client

Microsoft operating systems: Windows 2000, Windows XP, Windows 2003 and Windows Vista have built-in VPN software.  In earlier versions, it was necessary to install an additional program to setup VPNs.

Current versions of Windows allow to use both L2TP/IPSec and PPTP. With L2TP/IPSec, there are two ways of authorization: through secret passwords and digital certificates. PPTP authentication is available through MSCHAPv1 and MSCHAPv2, but they do have weaknesses in terms of safety. It is therefore recommended to use either L2TP or IPSec. Nevertheless, despite certain flaws, PPTP protocol is easy to implement and use, especially in networks which do not require a very high level of confidentiality.

Cisco VPN Client Software

Cisco VPN Client Software is a program that allows remote access from virtually any PC. There are versions for different operating systems: Windows, Linux, Mac OS, Solaris. Windows and Mac OS ones have a graphical interface, and the others are managed through command line. Cisco VPN Client uses IPSec to create a connection to a remote point, which precisely speaking is the Easy VPN server using Cisco Easy VPN. Easy VPN server may be set up with VPN 3000 series concentrator, that is, the router with an appropriate Internetwork Operating System (IOS), Private Internet Exchange firewall (PIX), or Adaptive Security Appliance (ASA).

Cisco VPN Client uses multiple solutions, some of which are consistent with general standards, while others were developed solely by Cisco. You have two hash functions to choose from: MD5 and SHA-1. Just as in previous examples, there are different methods of authentication available: secret keys, digital certificates, XAUTH (IKE Extended Authentication), and multiple encryption algorithms: DES, 3DES, AES-128, AES-256. The program can be easily set up the graphical interface shown in the figure.

Contrary to Windows VPN Client, Cisco VPN Software Client, does not support PPTP, and works with IPSec only. Both solutions are similar in terms of establishing a connection (to create a tunnel), but the engineers at Cisco went way beyond the IPSec standard, and added some ideas of their own, such as split-tunneling, IPSec over TCP, or reverse route injection. Therefore, using Cisco VPN Client Software gives you a lot more. This, however, does not mean that Microsoft's solution is useless. On the contrary, it does have some strong advantages over Cisco; for example, you can create installation packages that contain all the settings necessary for the maintenance of IPSec security policies, profiles and VPN connections, which greatly simplifies desktop management.

John is a contributing author who writes articles on numerous subjects, including network security and BartVPN, software. He has been in the field of VPN service for a couple of years now and feels very strong about the future of the technology.

About The Author

Related Pages

Connect With Ubscure