Proxy servers simplify connectivity
In my February 1996 through October 1996 Inside Out columns, I explained how to use a Windows NT machine as an IP router. Those columns' continued popularity surprises me. To this day, hardly a week goes by that I don't receive a note from some exasperated soul trying to attach a small or midsized business to the Internet by using an NT machine as an IP router. Turning an NT machine into an IP router is probably too much work for most folks. This month, I'll explain how routers differ from a usually more desirable alternative, a proxy server.
The Traditional Approach
Most companies connect their LAN to the Internet through a four-step process. First, they acquire a block of consecutive IP addresses from either Network Solutions or the American Registry for Internet Numbers (ARIN). Most companies hire an Internet Service Provider (ISP) to handle the paperwork associated with registering IP addresses. Second, they assign one IP address to each network card in the company; two machines can't share an IP address. Third, they lease a full-time connection to their ISP. Fourth, they set up routing.
Many people don't realize until they reach step three that they can't parlay their $20-per-month unlimited-access, dial-up Internet account into shared access for a group of machines with distinct IP addresses. ISPs can afford to offer only so-called unlimited access accounts for a few dollars a month because ISPs have a built-in barrier to network overload: a limited number of phone lines. In theory, your dial-up account offers unlimited access, but in practice your ISP has 10,000 unlimited access subscribers and only 200 phone lines, or ports. Some ISPs mysteriously disconnect unlimited access subscribers who've been connected too long. If you want a truly full-time connection, your ISP must dedicate a port to you, and you'll pay more than $20 per month.
Network pricing depends on the number of addresses and the connection speed. I recently started a new company, and I needed a block of 254 IP addresses for my firm. I found a wide range of prices for this size network, but the best deal I found was $400 per month for a 64-kilobits-per-second (Kbps) frame-relay connection. Nearly $5000 per year for 64Kbps might sound like a raw deal, but it's not, at least not in the Washington, D.C., area right now. I expect bandwidth prices to drop as the communications network infrastructure improves.
After you contract with your ISP for full-time access to your IP addresses, you'll need an IP router, a device that directs packets on your LAN to and from the Internet. You have many choices in the router market, but your ISP might recommend a particular brand. I've configured routers from Cisco Systems, Bay Networks, Ascend Communications, and Compatible Systems; I prefer Compatible Systems boxes because they're easy to configure. Alternatively, if you have the necessary software and plenty of patience, you can use a PC as an IP router. I don't recommend this setup, but I've used it in the past. After you configure your router, you're wired.
Proxy Server Setup
Setting up an IP connection to the Internet can be expensive and a lot of work, and establishing IP addresses can be more hassle than I described. You might have trouble getting as many IP addresses as you want. At one time, you could get blocks of hundreds of IP addresses fairly easily, but now the Internet is running out of addresses, so Network Solutions and ARIN limit address assignment. You might find that you don't want everyone in the company connected to the Internet; surfing is too distracting for some people. Establishing a policy that regulates who gets access and who doesn't adds to the time and effort you spend setting up a proxy server. And a full-time Internet connection might cost more in your geographic region than in Washington, D.C.
The alternative to the hassles and cost of connecting to the Internet through the traditional approach is a proxy server. To set up Internet access through a proxy server, you assign IP addresses that the Internet doesn't recognize (between 10.0.0.0 and 10.255.255.255) to all the computers on your network. These addresses let your PCs communicate with each other. Next, you connect one of your networked computers (let's call it PROX) to an ISP via a modem or Frame Relay Access Device (FRAD). Your Internet account can be a dedicated account or a $20-per-month dial-up account. PROX, your proxy server, then has two IP addresses: the 10.x.x.x address on its Ethernet card and a valid Internet IP address that your ISP provides.