1.5 Must I Use DNS?

Despite the usefulness of the Domain Name System, there are still some situations in which it doesn't pay to use it. There are other name resolution mechanisms besides DNS, some of which may be a standard part of your operating system. Sometimes the overhead involved in managing zones and their name servers outweighs the benefits. On the other hand, there are circumstances in which you have no other choice but to set up and manage name servers. Here are some guidelines to help you make that decision:

If you're connected to the Internet . . .

. . . DNS is a must. Think of DNS as the lingua franca of the Internet: nearly all of the Internet's network services use DNS. That includes the World Wide Web, electronic mail, remote terminal access, and file transfer.

On the other hand, this doesn't necessarily mean that you have to set up and run zones by yourself for yourself. If you have only a handful of hosts, you may be able to find an existing zone to become part of (see Chapter 3 ). Or you may be able to find someone else to host your zones for you. If you pay an Internet service provider for your Internet connectivity, ask if they'll host your zone for you, too. Even if you aren't already a customer, there are companies who will help out, for a price.

If you have a little more than a handful of hosts, or a lot more, then you'll probably want your own zone. And if you want direct control over your zone and your name servers, then you'll want to manage it yourself. Read on!

If you have your own TCP/IP-based internet . . .

. . . you probably want DNS. By an internet, we don't mean just a single Ethernet of workstations using TCP/IP (see the next section for that); we mean a fairly complex "network of networks." Maybe you have a forest of Appletalk nets and a handful of Apollo token rings.

If your internet is basically homogeneous and your hosts don't need DNS (say you have a big DECnet or OSI internet), then you may be able to do without it. But if you've got a variety of hosts, and especially if some of those run some variety of Unix, you'll want DNS. It'll simplify the distribution of host information and rid you of any kludgy host table distribution schemes you may have cooked up.

If you have your own local area network or site network . . .

. . . and that network isn't connected to a larger network, you can probably get away without using DNS. You might consider using Microsoft's Windows Internet Name Service (WINS), host tables, or Sun's Network Information Service (NIS) product.

But if you need distributed administration or have trouble maintaining the consistency of data on your network, DNS may be for you. And if your network is likely to be connected to another network soon, like your corporate internet or the Internet itself, you'd be wise to set up your zones now.