For some businesses, such a network is an attractive option. They might have a central office with a large network (and an IS department to match), connected to small branches with local file servers. The branch offices may be too small to have their own administrators or to be part of a WAN, with a large WAN pipe entering every office. If a great deal of data is regularly transferred between offices, however, a phone line network will probably be quite expensive. But an Internet network solves these problems: you don't need dedicated administrators or a large WAN pipe in every office, and you certainly won't incur long-distance phone charges.

Of course, such a setup is too good to be true for one simple reason: security. No one in his right mind would expose his file servers to the Internet without taking serious security precautions. First of all, you need to make sure that the users or servers accessing your servers are legitimate. Even with such security precautions, any enterprising individual can intercept Internet transmissions. A packet sniffer placed near the source or destination of those transmissions can tell a whole lot you don't want told. Faced with such risks, most administrators may well regard the Internet as too risky to be a viable communications solution.

Security and affordability
But a VPN is different. It permits secure communication over the Internet by encrypting data transmissions. In addition, it acts as a firewall for the file server, protecting the server from undesired visitors. With such security measures, Internet communications will be as secure as WAN communications. In short, a VPN provides both security and affordability.

Many recent news stories have highlighted the cracking of encrypted data. These decryptions have generally taken several days and required hundreds of thousands of dollars of computing equipment. Since most hackers are looking for the easiest approach to obtain secure information, it's unlikely that they will have the patience or the resources to crack your Internet-transferred encrypted data. If you're transferring data that has a value greater than the costs of decryption (both in terms of financial and potential legal costs) to somebody, then the Internet is not a good solution for your company.

Most VPNs also provide tunneling, or the encapsulation of a network packet within an IP packet. So if your servers run Novell NetWare and use IPX/SPX instead of TCP/IP, they can still communicate over the Internet through a VPN. The IPX packets are simply placed inside IP packets, sent over the Internet, and removed from the IP packets at the destination. This is not really an extra security feature, though, as encapsulation is not the same as encryption.

You don't need costly network infrastructure. A WAN requires network routers at each site, in addition to dedicated lines. With a VPN on the Internet, however, those routers are, quite literally, somebody else's problem. This brings the costs of a VPN closer to those of a simple LAN rather than that of a WAN.